Cometic are fine for the power levels you are running.

As with all head gaskets, head/block must be clean and truly flat and the head bolts installed correctly and tighness rechecked after a few hundred miles.

Often enough its the installation that makes the gasket fail !

The only thing I dispute about metal head gaskets is the number of times they say they can be re-used,
IMO, you should only use them once..... !