Do not know if this will work for everyone, just a consideration. Have seen a few guy's fold a towel over a couple of times (long ways), loop it over the bar, grasp the two folded ends, lift the elbows as high as they can to keep a amount of pressure on the bar (setting it against slips) and do front squats that way. The towel can even pad the shoulders a bit.
When doing front squats the heavier the bar the more solid it should set upon the chest/shoulders. The main factor being, if the elbows are kept high enough. Skinny people may have a problem when holding front squats because of a lack of muscle mass to pad or set the bar upon. Some experienced men do a hands free front squat or a cross over hand position. Either are really not holding the bar in any firm manner.
Of course the hand spacing, on the bar, will have a great affect of how controlled and comfortable the bar feels on the shoulders. Anyone try a curl grip when doing front squats? Good Luck.