On my pump (which I got new in the box with the adapters separate) there is just enough room for a tube connection, but not a flange. You are correct in that these pumps are really designed for flex tubing connections as opposed to metal seals or KF flanges.
Nonetheless, if you can work out the fittings, even with some diameter reduction, I think you've got a good pump for your fusor.
You don't need any insulation under the pancake. If you did that it would probably overheat.
Steve
Created on Sunday, April 15, 2001 8:48 AM EDT by Steve Hansen