The one time I used grease, it leaked. Always use Permatex or like product which never leaks.
Hylomar was developed by the RAF to stop leaks on Rolls Royce-Merlin engined Spitfires. You could say it helped win the war.I use grease never had a leak (yet!)
Rolls Royce use Hylomar Blue on their engines I think -they don't leak much either
Part of the reason that Hylomar is such a good sealer is that it never truly sets up - it remains elastic, and fuel does not touch it . . . so it is good for many things. I have it in cans with applicators as well as spray-on. I use the spray on for blown applications with 0-ringed heads.decks and solid copper gaskets - works really well. But - it is not cheap!
The words "good" and "cheap" seldom go together....