I used unsanded grout for my first creations and had some minor cracking problems (when drying). It also had a smooth texture which was even smoother once sealed. Unfortunantly my main piece was too tall (too close to UVB) so I am recreating a main piece and this time I used sanded grout. No cracking issues, cheaper, and 4 layers of sealant into the Mod Podge and I can't even tell the surface has been affected (still has a ton of traction/texture).
:headbang:
:headbang: