I've had good success with modified Smolov. Instead of going 4 times per week, I did it twice a week and removed sets from each workout. I think it was:
So it took 2 weeks to go through a cycle, then each cycle I would add 20lbs and start over. I started real light, and after 3 or so cycles, I did 10lb increments.
I kept the progression up for at least 2.5 months and got up to a 405x5 squat with this routine, which is not impressive by standards on this forum, but it was the most productive squat routine I've ever done.
I didn't need to cut back on upper body training or assistance, or do anything else strange in terms of recovery like force feed or quit my job and take naps, either.
Don't be afraid of higher reps either. Most people who get relatively strong, won't go above 5 reps. Some have reason not to, and others just get lazy.