Kingfish I wish I could find this long write up on max aitas squatting from Glenn, the short version is, he had gone and trained with ivan A. in bulgaria, with a premium on pushing his squat up since he was hurt/wrist pain. He improved quickly at first, then stalled for around a year if i recall correctly. Still squatting daily, he returned to cal strength and pendlay got him to go into a 5 x 5 squat program, with the exception he could continue his daily squatting. This gave him one volume day, which was all he needed and likely could handle with his daily squatting on other days.
after a few months he destroyed his previous pr's, I want to say it was by well over 100 pounds. The videos of those squats can be seen on the cal strength channel, the story leading up to them is golden though.
IMO, most bulgarian programs work around a steroid cycle. i can't follow a routine like that and recover with just steaks and eggs.
i agree with the incorporation of the volume day. looking at the bigger picture of my squat program, i'm actually pushing the top heavy single in order to get my sub max higher also. i've spent so many workouts in the past few years repping a single 405-425 and then dishing out an 8rep x 6-8 sets using 365-385s. the last volume workout i did without the pause reps was a 405x 4-6, 20 total reps.
i plan to do the same soon but seeing that i've used the 455x1 with a strict pause for 25 singles already, the 475x1 became mentally doable as a goal IMO. 475-425 backoffs, then a 495-455.. that would be a big lifting milestone for me. all paused reps. i've never been broken before.. not going to mess it up now.