Unfortunately Microsoft's store doesn't allow requesting more than 6GB of VRAM in a store listing, so that's why it says 6 and 12 in the same listing. The lowest I've tested so far is a 3060 12GB. I wouldn't expect 6GB to work, but if you're willing to give it a try I'd be interested to know what happens.

I'd like to support less VRAM. Maybe a future version will offload some of the processing to the cloud.