Front Squats are the best type of squat to develop strength in the cleans. The positions are the same. Control the eccentric phase being careful not to lose control at the bottom. Keep the chest high and the bar straight as you stand. Front squats will work the back a lot more than back squats.
Lifters will squat at the end of every training session. The end of the session is most common because you want to do all the technical lifts at the start when you are fresh and able to concentrate better. Sometime, I’d use front squats as a warm up exercise, particularly if training early. This would help wake me up and get the legs firing. I would recommending alternating back and front squats each session.