Hi, I'm using a Toyo 6X7 roll film back on my Toyo Field camera. The actual fil m holder on this back is a Singer and the reason I'm writing is the foam gasket that provides a light seal has turned to goo.

I assume that I can get some neoprene or rubber of some sort to replace the gask et and I'd like to know 1) What thickness of gasket would be approriate? 2) What product would remove the "goo" safely from the Singer film holder and the back? and 3) What kind of adhesive could I use that would be safe on the new gasket?