Hi Tim @timbrownfl, My mask leaks a lot also but what I've found out the past few years is that leaks are really not a big deal as long as you are able to reach your AHI target. Mine is an AHI of 4 or less and I usually a lot lower or under 4 per hour. The cloth comfort cover I use probably causes some of the leakage but I also don't tighten my mask too much because it hurts the bridge of my nose.

I also didn't have much luck with the chin strap when I was testing the under the nose masks and I had seen a YouTube video where a sleep therapist suggested wearing a soft neck collar that is used for neck injuries. I bought one on Amazon that was fairly cheap and it did the job of preventing the jaw from lowering to open the mouth. I only used it for a couple of nights because it wasn't comfortable when I sleep on my side, which is about 90% of the night.