When I was at the hydro store today I really wanted to up my pot size from 5 gallon square pots to 7 gallon (whatever type pots) I measured the width of my tent and it is 26". I took my tape measure to the hydro store and checked the sizes... The Smart Pot 7 Gallon was 14" across diameter which would have made them 2" too large for my tent. I considered squishing them in but I decided not to because they still would need larger drain pans to sit in which wouldn't work....Next was the round plastic pots. The 7 gallon ones were 12' in diameter which would have worked but also needed larger drain pans which were huge compared to the current ones I am using. I could have gotten away with squeezing them into my current drain pots but it would have left no room for runoff and would have ended up in me cleaning my tent because of spills... so those wouldn't work either. They didn't have 7 gallon square pots so I may have to see what other local hydro stores or hardware stores carry to see if I can bump up the size pots, if not I am stuck using the 5 gallon plastic square pots which are ok, but I would prefer larger ones.. the search continues....
Have you looked into those shopping bags they sell at the big box stores? They're like 6gl bags with handles and they drain well too...and...THEY'RE SQUARE