I am working on rebuilding a 50's road race car it's a mix of metal and fiberglass construction. Car was stripped of paint, metal/glass is straight and it was sealed and sprayed with 3 coats of high build. It was knocked down with 150 and is ready for finish sanding before base coats. So my question is, this thing has about 4sfq of straight body panels on it and everything else is curved or a gentle valley. Getting in and block sanding this thing at least the way I would do it in the past is all by hand or 1/4 inch rubber is going to be difficult to keep consistent side to side. A local old painter suggested using 3M grey and red pads (400/600 grit equivalents) by hand as an alternative to blocks and paper. This car is going to get raced and its going to get hit and repaired a bunch so this is not going to be a 10K in material job but I want the basis done right. 1. Has anybody done this successfully. 2. Is there a block that conforms to valleys that you like if this will not work that will hold its shape or that is adjustable with like a truss rod?