Underside first no masking
Then do the Inside, no masking, over spray of inside to underside is acceptable
Finally Mask off the doors and windows for the exterior color again you get exterior overspray onto underside if any at all
This order is based on factory overspray I’ve observed on Canadian built trucks
But whatever you want to do I’m sure it will look great
Generally I think spraying the most cosmetically important surface last makes intuitive sense because that’s the one you don’t want any masking to damage and also the surface you don’t want to overspray at all
But inside can be touched up worst case
And the underside didn’t matter at all, had any paint was good enough
-s
