front squats are a hard exercise, they require you to have a strong torso and shoulder girdle to hold the weight and stay in position, but they also dont let you "cheat" and bring in the back/hips as much as a backsquat... thats why some who can backsquat big weights cant front squat big. one of the guys down here has deadlifted 830lbs and squatted 903lbs, also he benched 606lbs and squatted 953lbs but got 2 red lights and one white on that big squat so no lift. he did come up with it easy though, just needed another inch of depth. anyway, this particular guy, who weighs around 260lbs, cant front squat 500lbs! hes strong for sure, but hes super strong in the hips and back, and not so strong in the quads. so to come up, he has to lean over a little, and you cant do this on the front squat or youll lose the bar. he just doesnt have the quad strength to come up in an upright position.
another guy who i coach, who has clean and jerked 440lbs, can only deadlift about 550lbs, and his best backsquat is only about 600lbs, yet he front squats over 500lbs. but if you look at him, its obvious where his strength is, hes all thighs. very small waist, about 30 inches at 235lbs bodyweight, abs and all that, but his thighs are freaking huge. so even though he doesnt have the hip and back strength to do the big squat and deadlift, he can come up with a big weight in the front squat with those strong thighs. just for trivia, this particular guy has also done an overhead squat with 420lbs, and came close with 440lbs. if you have done overhead squats, then you know how freaking strong this is.
so, i wouldnt worry too much about the ratio of the lifts. this is going to be determined by your body, where you are strong and where you are weak. ideally, you ought to be around 80-85% frontsquat to backsquat, but not many start out this way.
after coaching quite a few people who developed big front squats, i think that the best thing to concentrate on at first is holding the bar right (elbows up!) and getting a good, upright position in the bottom, and not leaning over while coming up. concentrate on form, increase the weights slowly, and eventually youll have a big front squat. i was never good at the front squat... really struggled with it. but over a number of years i increased to 550lbs for a pretty easy set of 5, probably had a lot more in me at the time, but didnt push it any harder than that because at the time i couldnt jerk worth a damn and wasnt going to be needing any more leg strength than that to stand up with what i could jerk, and wanted to use my training energy on jerking instead of killing myself with heavy front squats. so even someone who struggled with flexibility and form can eventually do big weights. dont give up if they dont come naturally.