Seriously I want all u guys to try the squat on your tippy toes. After normal squats put 135 on the bar and do a set of 15 on your tippy toes and tell me how bad your quads are burning.
Might I suggest doing Bulgarian split squats as a finisher.
Guys write this down and remember this moment. We agree.
Assuming you are squatting correctly I wouldn't care if you don't "feel" it in the quads. You are still using them, it's impossible not to.
So focus assistance on quads of so desired.
It appears you are suggesting some form of a sissy squat. Never tried with weight on my back. I have tried it as it was intended holding a plate across my chest. It's worth a try.
Personally, I'd rather load up and do hack squats over front squats. I'm not a fan of front squats for quads. Nope