Squat Advice

I am almost 40, 5’8", 176. I have recently shifted my focus back to strength having dropped a fair bit of unwanted bodyfat. I have had 3 knee surgeries (2 a long time ago and and one last year) and have been wary of the squat for some time. I can deadlift well (210kg 1rm) but my squats are coming up much more slowly. I have been doing Rippetoes Texas Method for a couple weeks and my squat has already jumped from a 1rm of 115kg to 140kg. I have gone back to basics this year and worked a deep squat from light weight.

My question is one of depth. Should I continue to squat deep now that the weight is starting to creep up? Or should I switch to a box squat (ie a powerlifting depth). I love the weights going up but I obviously want joint longevity as well.

Any advice is greatly approeciated.