first i think we need some numbers.. what are you squatting front/back.
also, are you a 'beginner' or have you been lifting a long time. it makes a difference.
a long time ago i ran a back squat program that was 3x5 for two months then progressively more intensity/less volume, i.e. 3x4 then 4x3, 3x3. i started this program with a 115lb back squat for one rep. i left it after about six months with a 265 squat. a lot of guys put up bigger gains than that too. these were by no means olympic ass to grass squats though. they were wide as hell powerlifting hip drive squats.
if thats why you do/are looking for, its all about consistently increasing your intensity (loading) and lowering volume (reps/sets) within a macro-cycle. its not science though. you'll know when you're ready to change the set/rep scheme to 3x3 from 4x3 etc. youll know when youre ready to go for your one rep max. however, you should always strive to increase the poundage if youve made your previous workout's numbers.
btw, this kind of gain (imo) can't be accomplished without a serious eating regimen.