I haven't been happy with any of the surfaces I've tried, including the blue foam, pink foams, drywall etc. I currently use Celotex - it's not the best surface, but it beats the others by a fair margin. I would LOVE to use 3/4" cork, but I haven't been able to find any anywhere. I need a 90"x30"x3/4" sheet of cork, if anyone knows where to get it.