Okay let's go on!

So you want to buy Boots + 5x Health Potion, okay.

Doran's Ring + sight ward against jungler. 95% of the time you'll be facing a jungler but you won't buy a sight ward instead of pot's everytime

greater mark of hybrid penetration > Greater Mark of Magic Penetration



wat?

Your runes section only show the Class 2 Runes. It's "GREATER Seal of Armor" for example instead of Seal of Armor

You mentioned Boots as starting Item, but not in the End Build. So you're selling them in the end or ... ?

Oyooy thanks for comment you're helping me so much with this guide. When I saw your comment I realized how many mistakes I made and I trying to fix them.

That's just mistake while fixing bugs.

only 4 points in E and 6 in W?

Problems:
You should have glyphs of flam mr not scaling, especially mid.
You spelt 5 things wrong before the guide even starts. That is not making a good impression and most people wont want to read on.
You can't start with 5 pots unless you wait and miss cs/not leash for jungle.
There is pretty much no benefit to starting with 2 pots instead of 4. The pot will give you enough sustain to get at least 2 cs making it pay for itself and more.
No boots.
Why buy gunblade? It would be a lot more gold efficient to get an AP item rather than a weak AP item with not much AD bonus for a lot more.
Can't max a skill by level 8
You are getting pretty much 0 benefit from some of your masteries. The dealing 5% extra damage to towers doesn't help. Neither does the tiny amount of crit chance or the benefit from critting. You just can't get weapon expertise because you need 4 points in deadliness as well as it being completely useless on teemo. Teemo is also not mana hungry or ability reliant so you don't need meditation. Instead you should have 21/9/0 masteries with AP masteries in offensive and durability, resistance, hardiness and veteran scars in defensive.
I am not sure what build you were using for the damage working out but using your recommended build I found the combined on hit and DoT of toxic shot was only 489.5. You also have to remember that people have resistances so you will never get near that amount.
"He is so fast that he doesn't need boots to be as fast as other champions (he's got that speed from Move Quick passive)" There is a reason why teemo has movespeed in his kit. He is very movespeed focused so benefits greatly from boots.
"Not Soo Good
Ignite - " Ignite is a good spell on teemo because it combines with his poison to give him a high kill potential, the same way as mordekaiser.

I think overall this build is impractical, overly expensive and in some parts, impossible.

My fault, but it is fixed now. Thx for comment ;D

Problems:
You should have glyphs of flam mr not scaling, especially mid.
You spelt 5 things wrong before the guide even starts. That is not making a good impression and most people wont want to read on.

E at level 1 and 2 seems legit

"26/0/9" Seems legit