I think it’s too heavy to use with the vented helmet strap, when I’m using the full face I mount it on the side and I like the results. I doubt this will work but here’s a video on FaceBook.
The Garmin handlebar mount is good,I got mine from Wiggle for a quite a bit below RRP. I have a bunch of cheap go pro mounts from china, the under saddle backwards one is also good but mostly they’re too flimsy, the Garmin mount is a really wide and stable mount.
I always try to mount it upside down though, that tends to help stabilise the hefty thing.