JimSmith

I didn't play the games referred to above, just the most recent one on "wasted material time and energy". First I'd like to say that doubling window sills is always a good idea over 4 ft. because it reduces warping. I've also heard a framer from California say it's common practice to double all window jacks so as to provide counterpressure against sill twisting (the jacks closest to the opening are cut to fit above and below the sill end). Might not be code but definitely not a waste of anything. Finally, where are the answers? Maybe you could make this a "teachable moment" for us unenlightened ones?

Thin coats, I would say. Painters refer to "sag" even when too much coat is applied in a vertical plane, so think about what would happen when you hang your just-painted or varnished surface upside down - or maybe let's not think about that. Maybe making 5 or 6 of these jigs would be more effective; that way the finish has time to get tacky or even set up before you spin the first door.
Cool idea but I'd rather just do it the old way.