When I was sanding my 53 I never did find anything real great to work with the curves. The best thing I had on hand that worked was a body filler applicator with the sand paper wrapped around that. It seemed to flex enough to follow the curve. I have the blocks that I think your talking about, they didn't work well on the fenders and corners, they were too stiff. I think the 10 minute thing is the minimum about of time between coats.