How much clearance do you recommend when parking?

Just depends on how good you are maneuvering your rig. I know I wouldn't have a problem, but others might have never put a rig anywhere that wasn't a 1 acre pull through. By the way I once watched a trucker back a double (2 trailer boxes) into a spot with doubles on each side of him. One shot and he was in. When he went inside I had to go down each side by sidestepping. Less than a foot on each side all the way back. WHAT A MAN!!!