What is correct pipeline for modeling characters for DFAO?

Hello.

I´m starting modeling my characters, but, since DFAO needs meshes to be CLOSED, how I will model things like t-shirt, pants, and other 2 sided pieces?
Make sense keep both sides of topology? Will me a heavy performance impact? Cast Inset Shadows can handle 2 sided meshes with only Ray Traced Shadows?

PS.: (I intend to not use cascades, only DFAO, like u can see here)

Skeletal meshes dont generate distance field mesh representation and you use inset shadows for skeletal meshes if you enable ray traced shadows for your lights, so it doesnt matter how you model them really.