Cool ideas!

I'll add that when you back off on stress day you normally have to back off on Performance day as well. Unless you'd been overreaching and were in a state of fatigue, in which case a back off will probably allow PR's to continue for a week or two, reducing the workload on stress day would mean there just isn't enough stress to spur PR's at the end of the week anymore.

Eric's offered some pretty good ideas. If you want to continue with triples on stress day though, just use the same principle but move up the sets instead of reps from 5x3 towards 8x3. That would be another option for a while.

Cheers,
Jeff

PS: Don't get too caught up with a 300 lb squat. You'll get there in due time.