I don’t know if it’s right, but on mags where you’ll need to be able to move them without ripping the gasket, I use Indian head to glue the gasket to the mag, then white lithium grease on the gasket that touches the engine.
We put a light coat of grease on both sides of the mag gaskets on our flight school planes. Makes adjusting the mags without tearing the gasket easy. No leaks either.