This is one of the points I made Rambo, how would one of these flexable blocks work when it is, well, flexable? I mean, why not glue the paper to an old bike innertube, it's flexable as well?
That is my point, how can a flexable "block" be a "block" at all? Isn't the point to use something that DOESN'T follow the highs and lows? The point of a block is to BLOCK the highs down to the lows isn't it?
If the block is "firmly" flexed into a position then what shape is it in? The shape of that roof changes a zillion times as you pass over it. So how can a "shaped" block sand it flat when it only it's shape only matches the roof's shape at one particular point?
Like I said, I tried them, the old long board that was plastic so you could curve it to the shape of a fender and it just didn't work and didn't make any sense at all to me.
I block curved panels with a hard block and simply look at at it as a "curved flat" panel. Just taking a bite sized piece at a time until it is all done.