pvc coping. We had a piece laying around in the shop that was perfect size for the long board sheets and I love it for under bodylines. I think dead body man recommended them to me before but without knowing I shot down the idea cause I thought it would be too hard of a surface. Usually I try to use the tear drop dura block for those areas cause it's the only roundish dura block that stays true, but for the areas around wheel wells it's too short to give you a true read when the dip surrounds the wheel well and is actually bigger than the block. The pvc coping worked wonders for that. Heading to home depot this weekend or try craigslist free section.