Muscle tissue isn't the biggest issue with powerlifting unless you're in a hypertrophy phase, CNS is what really needs the recovery.
Regardless, my point is that you should ideally be doing the same volume so the amount of days shouldn't matter that much.
For argument sake, say you are doing 10 exercises per week. You could do those 10 exercises spread across 3 days or you could do them spread across 6 days. It doesn't really matter, right? It's the same amount of exercises.
Now, if you're doing a ton of extra work to fill out your workout time during those 6 days... Yeah, recovery isn't going to happen optimally.
I believe historically this has been my problem with the more days a week approach. Working in a similar amount of accessories from a 3day/4 day program to a 4 or 5 causing too much fatigue. That and going too heavy on supplemental lifts.
6 days of powerlifting would definitely be unusual, don't get me wrong. I'm mostly referring to how the juggernaut method would work if it were spread across 6 days because I'm pretty familiar with it. I saw one program that was built by them that was 6 days... I don't think any day ever was more than 4 or 5 lifts and one day consisted of 3 working sets of spoto press and 3 sets of light tricep extensions, that was it. They actually recommend you avoid doing 3 days per week for most of their programming because it needs spread out in the volume phases. I've done their 6 day powerbuilding program and it was pretty intense... But I made fantastic strides on that program, although the recovery would become an issue if you didn't take the deloads seriously.
