I've had the same question as the OP but I'm 54 years old. I've got PPST3 but haven't gotten to the actual programing chapters yet.
I'm a late comer to SS but I've been lifting for a few years and trying H/L/M since I've stalled and reset a couple of times. Heavy squats and heavy deadlifts seem like a lot to recover from, especially being a bit older. I've wondered about moving the heavy deadlift to Wednesday with my lighter squats and OHP. My squats and presses would still follow the H/L/M program on Mon/Wed/Fri. So it would look something like this:
Monday
Squats 3X5
Bench 3X5
RDL 3X5
Wed
Squats 3X5 @80% of Mon
OHP 3X5
DL 1X5
Fri
Squats 3X3 Mon+5# (I got this idea from Andy's site)
Incline 3X5
PC 5X3 or DL 1X1 wed+5#
Sound reasonable?