Hello ,
Thank you for posting in the community regarding the best workflow with working with materials.
I recommend when importing your Revit project to use the Datasmith Exporter plugin with Collapse by Material so that things are grouped based on the materials. Once that is done you can apply/adjust the material as needed, save custom materials in the user library so you can reapply quickly if needed.
Once you know what material should be what in Twinmotion you can establish a substitution table and load it as part of the import process when making other options. Here is the link to the Substitution table article:
https://twinmotionhelp.epicgames.com/s/article/Twinmotion-Substitution-Table-Overview
Hope this helps and let me know if you have any follow-up questions.
Kind regards,
Vincent B.