I have recently achieved a glass like mirror finish on my Huntsman, using plasticote paints. The process was supervised via pm's with Shane off this forum, I am no expert, but wanted a superb finish. This was the process. Its a wood hull, sanded with 600, wet and dry, then 800, then 1000, it took ages!!
Sprayed halfords filler primer, it was rubbish, didnt fill the remaining imperfectrions at all. I have read on this forum, later versions of filler primer are not as good, also, it had some sort of reaction with the plasticote and started to crack.Sanded it all off, started again, now used a different grey primer. 5 coats, 800 wet and dry inbetween each coat. May seem over the top, and a lot of wasted paint, but if your boat is built for speed, you need a good finish. Final coat rubbed down with 800, then 1000 soaked in fairy liquid.
Now the first of 5 coats of plasticote, each one rubbed down as above,there is no quick way of doing this! When I was happy with finish, polished with a bodyshop cutting paste, the sort that is used with a buffer. The trick here is to do it fast, as the polish is designed to work when hot, so I had to work up the temperature, being careful not to polish through the paint. The final process was then polish several times using cream car polish. It was then left for a couple of weeks in the warm to harden, as I dont have a pintshop oven!
Dont use clear plasticote laquer, I tried it, and it drys like hammerite, and you cant flat it off as above and polish it up .
With regard to you overspray, use 1000 or 1200 wet and dry, soaked in soapy water, and use a block, not by hand, the overspray should come off, if it doesnt, then you are no worse off as you will need to paint it again, at least its worth a try!
Paul