lvtrojan a lot of people report good muscle growth with squats at 15-20 reps to failure, this exercice being the only exception to the low-reps-high-weight-is-what-makes-you-grow "rule" as per many good trainers.
Personnally, 10 years ago I had a very major hernia at the l4-l5 disc and my very reputed orthopedic surgeon told me if I touched a weight again in my life, I would probably never walk again. No surgery was suggested though.
The pain was always there, and of course I wasn't training. After a while I went back to the gym to do some chest/arms work, and the pain diminished. 3 months later I was sqatting again and the pain was GONE. I'm not saying that this WILL happen to you. What I am saying is that MAYBE your back will adapt to squats, your form as well, and eventually your spine gets strong again and someday you can squat heavy again.
What I would do in your place is to begin the workout with the leg press and finish off with the squats. This will let you recruit the other muscles that the leg press doesn't train so directly, without having to quite rely entirely on squats for your quad growth. Try the FULL squats, too, as they require less weight.
Also, doing a lot of back extensions, spine-stabilization exercises and ab work helped me protect that vulnerable area. 5 years after the hernia I was deadlifting 405. I know, that's no superhuman weight, but with my condition - Remember, the doc told me I risked becoming a CRIPPLE! - I was amazed.
I never have pain anymore, and the only thing I can do is wish you the same. How long has is been since your hernia, and what kind of surgery was it?