Heat sink glue?

[BrianG]

That's where I got my compound a while back. Good place to deal with and fast shipping. You might even get it by Saturday.

Actually, you DO want the heatsink to touch the FETs somewhat. The epoxy compound should be just thick enough to fill in the microscopic valleys and pits in the surface of the FET and heatsink, and to allow proper adhesion. The heatsink actually contacts the plastic case of the FETs, which is non-electrically-conductive - it's the leads you don't want to short out.