Read the OP. He back squats. He's 6'2" and his goal is bodybuilding. How do you know that he shouldn't use these machines?
Both look very similar, don't think it matters much which one you use. Use whatever feels best.
I don't think anyone sees any problem with unorthodox front squat grips for people who don't plan to do oly lifting. Think Poliquin "approved" it a few years ago. Good enough for me. And I think you can lift pretty impressive weights no matter what grip you use. Meat did 605 or so with crossed arms, H4M did 4 pps or so "no hands" and so on. Whatever works for you