I use 12" durablocks for wet sanding but never found a longer flexible block that I like for 800/1000 wet sanding clear on contoured surfaces. I took a 12" block and ran it through my bandsaw cutting the factory moulding line. This gives me a longer block that is about 1/2" thick that still cuts flat while making contours. The next one I might cut 3/4" thick for a little more rigidity. I like this setup and if you haven't found a good setup for this type of blocking then you might sacrifice a block also.