Think about this. In the unlikely event of a crash a mount SHOULD break and protect the crankshaft. Smacking Mother Earth with a durable mount will also dent the piston sleeve with the piston. A glass mount is designed to be a bit fragile.

I've flown several planes of .40 size with nothing more than self-tapping 1" hex head screws threaded into undersize drilled holes, then backed out and Locktited. It's actually easier to visually check them as being tight. A missing nut is hard to see in an enclosed cowl.

The fellers here who don't lose mount fasteners may be the type who carefully balance their props, too.