League of Legends (LoL) Question: Essentials and Gameplay Mechanics of Vel'Koz

Simple Intro (Just for fun): Hi, I'm GrovyleGrove and I'm seeking some advice on my current playstyle when using Vel'Koz, the eye of the void.

Side Note (Please consider): The following article, aside from the backstory, primarily pertains to the gameplay of Vel'Koz in the mid-lane role!

Backstory (Optional, can be glazed over): Vel'Koz, also known as (aka) Vel, was one of the first free rotations (refreshed every Tuesday) available when I started League (back in January) and I instantly fell in love with both the champion, their lore, and, most of all, their playstyle. Just a few weeks into the game and I was already saving up for the small luxury that was Vel'Koz, finally having the influence points (IP) to afford the cross-dimensional sentient we all know and love today after two miserable months of getting wrecked and flamed playing player-versus-player (PvP) jungle Nunu at a mere level seven or so. I had to have played at least three games a day that week when Vel'Koz was on the rotation, scaling to five my first few days after my purchase. The combination of his sustain, burst, and slight utility is why I love playing champions like Vel and Gnar.

The Research Behind This (Helpful in both better understanding the question(s) at hand and explaining Vel'Koz to those unfamiliar with the champion): First off, I have to give a big *clap* *clap* to AMP2010 and their amazing guide on Vel'Koz. AMP's video guide is a must for anyone looking to learn aboutVel'Koz. And while this guide went over many basic, intermediate, and even some advanced level game strategies, I was still left with many questions concerning the champ after reading the article (as well as many other).

Questions and Concerns (The "good" stuff): Vel'Koz's home page indicates that Fizz is one of the easiest laning champions to face. Many guides, on the other hand, suggest that Fizz is one of Vel'Koz's most formidable foes. Is this perspective wrong, or perhaps dependent on one's gameplay style for Vel? (Case 1) Although it is common knowledge, an artillery mage, by definition, is slow. This often leaves Vel unable to fend off the "oh so notorious" stuns, slows, and silences that can easily end any champion, but especially low movement speed (MS) characters such as, but definitely not limited to, Vel'Koz, Xerath, and Ziggs, ganks being one of the most difficult challenges with these types of champions. Sure, his kit allows for some lead way; in particularly the slow on his Q, Plasma Fission, and the stun on his E, Tectonic Disruption. Even with summoner spells such as Flash, Heal, and Ghost I often feel as though this is still not enough to escape many late-game situations against champions with the ability to gap close, leaving highly squishy champions like Vel in a very unforgiving situation. Could this be a personal issue, or potentially a recurring issue with the champion? (Case 2) This build into my next two cases. The first is one that has bothered me for quite some time, summoner spells. Unlike most champions, Vel'Koz's spell pick seems more interdependent on the team compilation since all spells can, in some ways, adapt to Vel'Koz's playstyle. While I would assume that this can really just apply to any championtechnically, is there any cases where I should focus my spell choice specifically on my laning opponent versus the team comps? (Case 3) Secondly, building off my previous mentioning of gap closing, although Vel's E stun is often used to deflect gap closing, should I ever use this offensively to build his passive, Organic Deconstruction, during team fights when considering its affect of area (AoE) potential? (Case 4) A lot of times, it seems as though the passive effects on items outweigh the pure power associated with Rabadon's Deathcap, yet it is considered an essential to Vel'Koz's build. How can I determine when to purchase it over other item options when pure ability power (AP) is applicable to any fight? (Case 5) Much like Ahri, Vel'Koz can be very mana hungry during the early-game, his auto-attacks are fairly weak throughout the game, usually making last-hitting a task easier said than done. Many use Vel's W, Void Rift, as a tool to add onto their creep scoreX (CS), but this often comes at the price of much needed mana and one (of the possible two stacks) of your main ability for building Organic Deconstruction, sometimes leaving you without the power to finish off your opponents, tracking back to the MS problem aforementioned. What is your method to efficiently farming with Vel'Koz and how do you balance your mana from falling behind? I'm curious to hear how some may tie in the added mana regen bonus of Plasma Fission into this scenario. (Case 6)
Speaking of Plasma Fission, many opponents will walk into the ability's split bolt when I activate the ability into a wall. While I understand that both enemies cannot see the ability when activated on a wall and that I can reactivate the ability early to keep the distance of the ability unknown to my opponents, I often use this as my main means of early, and sometimes mid-game poke damage, often avoiding using Void Rift to save mana, unless I think that I can get all three of my Organic Deconstruction stacks from the ability combo, much like Gnar and his passive W ability, Hyper. (Case 7)

Brief Summary (To put it all together): These are all of the questions that I can think of for now, but I may post any more that I come up with in the comments section and I encourage everyone else to post any questions that they may have as well. I do not expect anyone to answer all of my questions and would appreciate if you answer even just one of the previously stated cases to which you can use the numbers of to better help organize your statement. I'd like to thank you just for reading thus far, and also, therefore, give my acknowledgement in advance to anyone who has or will contribute to this post. Admittedly, I'd be totally psyched to get a reply from some of the well known "vets of Mobafire" such as PsiGuard, who is not only a Vel'Koz player, but also a great Q&A reference here on Mobafire, or even VaporaDark, who's in-depth guides I use on a regular basis. Your advice is admired in any way, shape, or form (post, link, or, for those who want to go the extra mile, custom battles). Feel free to chat me up as well, just send a message to the username GrovyleGrove. Best of luck to everyone! May the odds be ever in your favor! And for the big exit...
Sorry guys, it's just not the same without Neil DeGrasse Tyson in it!