I think the back squat contributes as much or more to the clean for two major reasons: 1)you handle much more weight and 2)you learn to drive out of the bottom position more efficiently(butt, then quads). Also, I think getting up from cleans gives o. lifters a lot of front squat work.
I usually have lifters train 3 days per week on squats and use about a 4:1 ratio of backs to fronts. And, I feel the front squat 1RM should be about 80% of the back squat max for lifters. I also feel that the max deadlift (from the clean set positi on) should be aboiut equal to the max back squat.
My wife, Suzanne Leathers, for instance, always did many more backs than fronts and never, ever had trouble getting up from cleans. Her max clean was 127kgs as a 75kg lifter.