Verdict:
Blackhawk Omnivore holsters are great, they are universal but very secure due to their active retention which is applied to flashlight (or 20mm mounting bracket if non flashlight version) and at a reasonable price.
It’s not always the easiest for us southpaws to find good holsters but this one works.
if you are looking to mount it to a QLS system though you will need an adaptor as the two are not directly compatible.
https://www.thingiverse.com/thing:4948094/files