Might suggest a Manta Ray squat pad. Or there are similar devices out there, search required. The Manta Ray helps balance the bar/weight ratio much better.
Or, as a alternative, front squats which can hit the quads very well. Even BB Hacks. All kind of leg machines around also.
If your in recovery and 38 years old, why the need for bar squats now, let the back heal to 100%. Backs can be very tricky, when you think their ready for some serious stuff you might be in for a surprise.
Good Luck.