You're welcome. It's something I needed, glad it's of value for you guys too!
Audio isn't exactly in sync. I've done some testing and it's not even consistently out of sync, but it's only a few frames, so that's a quick fix.
I haven't tested any modes for recording, just a few simple 16:9 non crop 11..8 bit lossless recording with audio, but please try every single combination and post the results!
Regarding the preview image, isn't it an option to sync based on black frames at the end of the recording? Might take a bit more time in post processing, but at least you get to keep the preview images.