Hi, first of all thanks for the kind words it makes writing this whole guide worth it! I would be happy to go a little in depth into the uses of Howling Gale and Monsoon.

I'll talk about tornado first. Let's think about the basics of the ability. It is a skillshot that can be send forward up to three seconds after the initial cast, and on impact, it deals damage and knocks enemies up. So, let's think about how best to use the ability, both offensively and defensively. As a damaging/knocking-up skillshot, it can definitely be used on the offensive. Offensively, its ideal use is probably to set up for your allies to do damage. The knockup is pretty long, so your team has the opportunity to follow up. Melee champions such as Jax can jump to them, engage champions/junglers such as Zac/Lee Sin/Elise have an easy target that won't move around, and Ranged champions such as Miss Fortune can unload their combos (Miss Fortune can ult on the spot and get a majority of it off). Essentially, think of it as a damage freebie! When you get three or four people with a single tornado, that makes the likelihood of winning the team fight increase tenfold.
I want to talk about the defensive capability of this ability next just really briefly since you did say you knew how it works. Since this ability has the potential to disrupt the engage, a lot of champs get countered pretty hard by Janna. Additionally, since you can time when the tornado goes off, its a great counter to teleport/zhonya/guardian angel, since you can plan for it to hit the teleport champion the moment that they are targetable.

As for the ultimate, I would say it's the hardest ability to get down for Janna. I definitely mess up my ultimate sometimes, and it's a skill that gets better with practice. Let's break down what the ability does. This ability knocks back all enemies on cast, and heals allies and yourself for the next few seconds. This means that there are three scenarios to use your ultimate in: a situation that needs the heal, a situation that needs the knock-back, and a situation that needs both.
The first situation is a little rarer since it's probably better to recall than burn an ultimate, but if your ally is on the verge of dying and they really want to stay in danger, ulting just to heal might be a good idea. This might also be useful when sieging the enemy team; if you won a skirmish and need to push, you might want to ult so that your team can push safely.
The second scenario is the knockback. I tend to use my ultimate for the raw knockback to mainly disrupt combos. For example, if a Zed ults me, I usually just ult right away so that his full combo is disrupted. I also use this ability just for the knockback if there are multiple engagers coming in at once that I can't disrupt with a single tornado. If Vi is coming in from one side and Camille is coming in from another, a well placed ult screws both of them over, and since engage champs heavily rely on their engage ability to win fights, it might screw them over as well.
The third situation to use your ultimate is when you feel like your team/ laner is getting edged out in a fight/skirmish/team fight. The knockback gives your team time to reposition and wait for ability cooldowns, and the heal gives them the extra sustain your team needs to win the fight. This situation is probably the most common.
The general guidelines that I would give for using the ultimate is to use it earlier rather than later. The heal is given over time, so using it super early on will maximize the healing value. However, I will say that this normally kills the knock-back part of the ability, so ideally, I would aim for the sweet spot where you can disrupt an engage and heal at the same time.

I hope this answered your question! Let me know if it hasn't and I will be happy to answer any follow ups that you have :)

Hey, thanks for including this suggestion! You are totally correct this works really well in the current healing/heavy meta so I appreciate your comment!

Hey first of all thanks so much for reading my guide I'm super glad you found it helpful! I'll try to answer your question as clearly as possible.

First of all, if there's a 15/2 Rengar on the loose, that game is definitely 99% wrapped up. With that kind of damage, skill kind of doesn't matter, unfortunately. However, the game begins with no kills on the map. Essentially, what I'm saying is that you shouldn't be trying to desperately figure out ways to prevent a 15/2 Rengar from one-shotting everyone on your team; you should be thinking of ways to prevent that 15/2 Rengar from existing in the first place by cutting him off in the early/mid-game.

I think it's good that you're roaming, and I would consider that your best shot at turning games. First of all, something to keep in mind is that it's never too early to roam. If you are at your fountain and see your top laner turtling while the enemy laner has half health, you should probably walk over, even if you are only five minutes into the game. If you gained priority in lane and see a fight happening in botside jungle, you should go. Janna is a champion that provides value really quickly- her shield is immediate, her tornado can be flung relatively quickly, and her w is a fast-moving point-click. Thus, you can make huge changes to the outcome of a game as long as you have good macroplay.

As for trash ADCs, this sounds a little rude but I would ditch them. I'm mainly saying this because ADC is not the best role. A good ADC can definitely carry, but other laners and the junglers are definitely the more dominant powerhouses on your team. Even if you get your ADC fed, a bad ADC gets popped regardless of whether they have a kraken slayer. If your ADC is pinging you for roaming, just mute them. Harsh reality, but you are a support for your team, not just for your ADC.

Finally, I would suggest customizing accordingly to maximize the chance that your team will survive. For example, I would build things such as moonstone renewer, locket of the iron solari, and redemption, since they are items that prevent your team from dying. It's definitely the best way to make sure that you are able to shore up the weaknesses of your team. Bringing exhaust is also a good idea, since you can kind of make up for solo laners feeding. If the enemy fizz gets super fed, exhausting him can shut down his burst and turn the game.

I hope these things helped! If you have any other questions, feel free to ask~

Hey, thanks for showing interest in my guide! It means a lot :) I'll put a TLDR at the beginning and then give you a better explanation below as to why I feel the way I do about Shield Bash.

TLDR: In my opinion, it's not worth it because it provides subpar/average value during the early game and decreases in value mid game and late game.

My general thoughts about shield bash are that the damage is a nice little tick, but the downsides of the rune are a little too big for it to be a popular rune choice on Janna. The biggest criticism I have about Shield Bash on Janna is that the mana cost and cooldown of her shield is really high during the early game. Thus, even if you make the decision to spend 70+ mana on a shield bash-empowered auto, you also leave yourself shieldless for at least over 10 seconds. Besides mana and cooldown, Shield Bash has really bad scaling; as Janna's priorities shift from poking to protecting, Shield Bash doesn't help that transition very much. Lastly, it's a matter of opportunity cost. Bone Plating works so well to protect Janna against early game poke and it has the potential to keep her alive in the late game, so I wouldn't consider Shield Bash to be the better rune in most situations.

It's definitely a rune to consider in general though, so it's great that you're asking. I had the same thoughts, which is why I tried it. I consider it to be viable on Janna; it's just a matter of whether its worth using this rune over another. I would still give it a try, since your experience with this rune could be a lot different from mine.

Hope this helped!

I'm so glad you found it helpful!
If you have any questions that the guide didn't answer, you can always come to this discussion board to ask :))

Thanks for reading my guide! I'm happy to help :)
If you have any questions, feel free to put them in this discussion board~