Best Baffle Material

I have been following the thread on baffles. What is the best baffle material for an ATM? Obviously, something thin and "knife-edged" would be great, but probably hard to fabricate and attach in a typical sonotube newt. Any suggestions? I've been thinking of using 1/4" flat black foam core poster board and cutting and shaping with a router.
Thanks!
Dave

Leslie,

How are you going to attach the weather stripping - contact cement? I've found that the adhesive that comes on the weather stripping foam does not hold very well.

Dave