Flat newly painted panels on or off?

[TwinPlenum3500S]

A question, I have a complete P6 in panels lined up in my garage, ready to be painted. When painted are the panels best flatted and polished on or off the car?

Off seems best as to avoid compound getting absolutely everywhere, but I would assume almost impossible to mop awkward panels like wings and quarters on bench.

Anyone got any good tips :?:

 

[harveyp6]

I have a mate who was spraying P6's from the early '70's onwards when we were at a Rover dealers together and he always mopped them when they were off the car, (on his own with no-one holding the panels, just had them on the stand they were hung on for painting) then he would hand finish them once refitted, and it was a treat to watch, but even he had a few panels get away from him. Not for the novice I wouldn't think.
Incidently I'd never paint whole panels on the car, I always take them off, blow ins are a different matter though.

 

[Mad_Dan_Eccles]

I think it depnds on how much room you have to work in. I'm in the middle of the same job; valances, decker panels and the like are definitely easier to work on when they are off the car unless you like working in awkward positions