Size doesn't matter, it's how you use it!
But in all seriousness, I used an 11" Mya Bambino and got some of the biggest smoke you could ever imagine. If you click my Youtube link in my signature you'll find a video that says "Hookah Insane Smoke"...that's the one. I do recommend a Nammor hose, decent bowl, and depending on bowl size and shisha tobacco, if you smoke something wet like Al Fakher or Starbuzz for instance, try using more coal. For instance, with the standard Egyptian bowl I use 2 coconut coals and get great smoke, but lots of times I'll push my luck with a Vortex bowl and use 3 coals for some head turning smoke density
Hope this helps,
- "The Phenom" Mohamed