Porting VRC avatars to CVR was pretty easy. They use the same Unity version and there are automated conversion tools. But even when doing it manually, it's literally the same as either VRCSDK2 or VRCSDK3 depending on the method you go for.
The only difference is that the toggles menu isn't as good as VRC's, but I found myself needing my toggles a lot less now that props separate from the avatar are a thing.