Practice at home with a "Blue Gun"
I bought 2 blue guns (Midway USA has them) for just this reason. I use inside the waistband holsters and want to make sure I don't angle towards my body when reholstering.
I would worry about the pants falling down. With my keys and wallet, that is the tendency when my belt is loose.
Once you are confident at home, try it for real at the range.
Please, join the NRA.