Ron,
When I was actively working on Fiberglass Boats and getting parts of them ready for paint, my Mentor told me to grab any old Spray bomb type black paint. He generally used Rustoleum cause it was super cheap. LOL
His explanation for the "guide coat" was, all you are looking for is high spots and low spots. You don't spray on a coat like you are trying to cover everything, you just want enough so you can see where the highs and lows are. It's all going to get sanded off anyhow.
His approach worked like a charm for me, anyhow. Just some insight and not meant to get people running for their Popcorn. LOL
And PS, the engine and frame are looking really good!!!!!
Oh, and I have no idea why Honda did that with the #2 & #3 spark plugs on the 550!!! But there is a flexible shaft, maybe wire, kid of like one of our control cables only thicker. Maybe you can use something like that to put those plugs in with a thin wall socket?
Something like this
http://www.ebay.com/itm/like/261661433758?ul_noapp=true&chn=ps&lpid=82 Charlie