Prepping car for paint

I think this seems like the best, I just want to do as much work as possible before I take it to a body shop for them to do the finishing touches and then paint
Some shops don't like someone else prepping a car before hand, I know I don't like it. A customer says its ready for paint except for these spots only to find out the car is a wobbly mess. You might be farther ahead to let the shop do it all.