I've never seen the rear of a the calipers, I assume there is 2 arms then and one pivots - so when the handbrake is pulled the 2 pull together and apply the handbrake.
So you are saying with the handbrake re-attached and in down in the car - make sure the arm moving arm goes back all the way? - Assuming it doesn't this is when the handbrake needs adjusting. This is I believe done in the car right? - tbh I'd just take it to a garage at that stage? I'm not sure how much tension there should or shouldn't be?
Tempted to just pay for it to be done anyway, ****ing hate working on cars!! Just average garages never do a decent job and properly strip and clean all the brake dust in my experiance