Jim,
I tried the clear Lustre Kote paint on my H9 cub which has the same covering and it took real well so I may use it..still undecided. I have heard of some using PPG on Ultra Cote with good results. Not gonna rush...I don't want to go back and have to re-do anything either. As far as floats go I built mine for my unfinished BUSA 1/4 scale cub with a G38 but again i'm still undecided. My floats are 46" May make the DPM cub a land lubber with wheel pants. Lots of time yet for final decisions. I've used the blue foam for many years, hard to find but I used the 1-1/2 pound density and it was the polyurethane foam, the only one that will accept epoxy. Sanding it leaves little particles floating in the air and on your clothes, best to wear a mask. Keep us posted on your progress, especially the interior.

Bud