Does anyone think this crust recipe would work for a galette?

I suggest you contact the original recipe author. It is likely that she has tried this crust in other preparations and may be able to comment about the specific use you have in mind.

I think it would, however I would let it rest for longer than 30 minutes. When I make gluten free pie/tart crusts, I always let it rest overnight since the grains/starches often take longer to hydrate.