I suspect the problem is that your wrists / fingers aren't flexible enough to bend backwards yet.
The bar should rest comfortably on your delts IF you keep your elbows up:
You don't need to grip the bar with your hands - and most people don't have the flexibility to do so.
When I started out I did a lot of stretching the wrists / fingers back. Pulling them back with my other hand. Pushing them back using a wall for leverage. Pushing them back using the bar to help stretch them. Things got significantly better in a couple weeks.
Maybe you do have odd athropomentry such that you can't do it...
I'd love to see vids if that is the case.
EDIT: You do need to be able to whip your elbows up around the bar for powercleans. I mean... What the hell else are you gonna do with your hands? I'd be pretty confident that you can stretch things out for the rack position with a bit of persistence and patience.