If you haven't seen it yet, check this link out.
http://www.ft86club.com/forums/showthread.php?t=102610
I didn't get the chance to test noico for damping, but it does hold up to 400 degrees in the heat testing.
My personal recommendation based on my testing is Sound Deadener Showdown's CLD Sheets. They are the absolute best weight to performance product out there, and is very reasonably priced.
The reason I suggested 80hz, is that I have a pair of L6SE's. I actually sent them off to have the analyzed by someone who did Klippel testing, which is the most advanced speaker test procedure out there. It tells you what the speakers real xmax is, based on distortion. The L6SE is rated from Hybrid Audio at 9.5mm of xmax, but the Klippel showed that the speakers reach 10% distortion at 3.2mm. What that meant was that they really couldn't be crossed under 63hz, and would be better at 80hz. I would expect a similar experience with the Clarus midrange.