Hey dudes, this was a great discussion. I think the main point should be the greatness of CoCo and how versatile it can be to suit many needs of growing.
However, if you want to get the full benefits of CoCo "hydro", I do not recommend anything bigger than 2 gallons. I personally used 1 gal pots, and the size of the plants was really determined by genetics and not pot size. The point to having such a small pot is to decrease the time it takes for the pot to dry out. So ideally you want to be feeding more than 2-3 times a day to really get the hydro benefits. I usually max'd out my timers schedule at 8 feedings a day but my plants could take more.
I do not recommend using perlite using my method as the roots will fill up the pot, and there is no need for perlite.
If you are going to use 2gal or more I would use something like rice hulls or red lava rock.