A lot of those questions are determined by what you are pulling. I can turn 90 and have no rail clearance issues pulling a Grand Design 303RLS. Runs a couple of inches high. Nose height and rail clearance really aren’t different than any hitch. I could make it ride level, but rail clearance would be tight. You also have to realize that bed clearance can go away instantly with a very small difference in truck and trailer altitudes.
I’ve never needed blocks to hitch or unhitch, but I can see it could be possible to get in a situation you might need to.