Originally Posted by LS-57
In my experience you should have the car assembled and all panels adjusted to their final resting place before final sanding. This way all the lines can be sanded from one panel to the other thus giving a cleaner transition from panel to panel. Make sure the door edges and such are good otherwise you'll end up with a thick edge which makes it look like a "bondo bucket".
For most paints I'd recommend stripping the car apart again for painting so you get paint on all back sides and no join lines in the jambs and such.
Great to hear, this is exactly what I was planning on too.