I've used chains quite a bit. First time with the wider stance. Pr at 470 with narrow stance. I have not done reverse band yet.(I have with DL) I figure a sticking point there at around 450 with wiDE stance. Wondering if a 430 (avg of 411 bottom and 451) every 2 minutes for 5 sets would increase power through that section. Just thoughts...I failed 475 but felt it was purely technique. The weight felt good and relatively light on my back. Simply lost it holding my position out of the hole.
I would suggest pauses at that sticking point. You could even pause more then 1x in the squat. You could pause in the hole and then again at the sticking point to really make you stay tight and also work that sticking point. I think squatting with weight w/o a pause where you have to work (grind) through that point would also be a good idea.
If you think there is a technique issues where you lose your tightness in the hole I like reverse band squats to help with this b/c since the weight is considerably lighter in the hole which allows you to focus on that issue and gives you the ability to make a conscious effort to address the problem. You can also do this with chains but the change in the hole isn't as drastic.