I do regret using my 10 gallon pots a bit, but since I plan to take em outside, I am hoping what that does is allows the biology of my living soil to be easier to maintain since I try to keep it around field capacity vs letting it dry out as much as a traditional soil and nutrient/water schedule. Mine is essentially water only, supplemented with some molasses water and compost tea from time to time. Still working on getting that exactly where I want it to be, but my photo plants seemed to really love it with 85% water only.
I do plan to LST, it seems genetics and strain may play a role in how well that helps or not, I am sure every situation is different, but it looked rewarding to me. I feel like if I was to grow many small 3 gallon sized auto plants that leaving them be might be good for more a mini SOG or something lollipop style. My buddy has gotten some pretty large auto flower plants though and I am fairly certain he uses larger than 3 gallon pots.
I am new to controlling my own grows vs working on others gardens and farms though, so despite having a lot of experience from start to cure, its still a learning experience for me and my own environment, as well as growing "my style" so to speak. <3