fzdev

From the Twinmotion product page: From the Unreal Engine product page:

In our testing, all mapping types are translating equally well.

Here's the great thing about this system: Any material overrides you've applied in Twinmotion should stick. (We tag each exported entity with a unique identifier, so Twinmotion/Unreal can keep track of them.) Just export your model from formZ again, under the same .udatsmith filename. In Twinmotion, go back to the Import area and click on the refresh button just above the icon of your Datasmith file. Please give it a try and let us know if you have any issues.

Des, Regarding your tip #1, surface objects are properly imported into Twinmotion (and Unreal Engine), but are visible only when the surface normal faces the camera. If a surface is facing the wrong way, you can reverse its direction as you suggest (using formZ's Reverse tool), OR enable "Double Sided" materials in export options.