Hey,
You just flipped to 12/12 this week so now would be the best time to lollipop, and defoliate, because it's going to still grow a lot more over the next couple weeks. Much of what you remove will probably be blocked by big leaves again here in 2-3 weeks.
The walls not a huge deal, but of coarse the less the better. more room, happier plants, more airflow, no leaves getting moisture buildup between them and the wall.
Happy flowering ✌️