low bar back squat form

[Jay L Swan]

Hi folks--first time poster here. I used to follow the Crossfit forum quite some time ago, but ended up here for the same reasons that many others have.

I have just started experimenting with the low-bar back squat and have a few questions:

1) How do you keep the bar from slipping down your back as you get further into the set?

2) While the low bar position feels much better on my back and legs, the arm position is painful. Any tips on this?

3) My "gym" does not have a proper power rack, only one of those squat-rack things with the angled bars and multiple pegs. Any tips to avoid amputating my fingers while putting the bar back in the rack?

Thanks!