@odf: MD material properties are difficult to 'translate' into Poser. MD uses different properties in u and v (weft and warp) directions. Originally u was weft and warp was v, and you changed the orientation of the fibers (the direction of the grain) by rotating the panel in the 2D view. Since MD5 or so orientation is an independent parameter. Poser has none such and uses same properties in all directions. MD supports non-linear properties (fabric properties are highly non-linear). Poser cloth room just uses linear. Last but not least: MD uses true strain, that is strain relative to vertex distance when pattern is flat. Poser uses strain relative to '3D zero'. That's why results from Poser cloth room tend to look saggy: any strain already baked into the zero mesh is amplified.

Then there are no determined properties for linen, wool knit or cotton. The library in MD is a brave attempt, but properties given there reflect measurements on new 'fresh from the loom' fabric. This may be acceptable for the fashion industry where the catwalk show is the highest degree of use, but it is totally wrong for the torn and stained mantle of the hero who after a long pursuit finally faces the dragon in a hot cave. In MD I always tweak the parameters until it looks the way I want. If I use the Poser cloth room I do same.

As for mesh density for export: I use 15 mm as a default for a normal garment. Higher densities make simulation times go through the roof if not kill Poser. For local details I sometimes go more dense. For large areas much higher. MD accepts up to 800 mm or so. This is a way to save model size for panels that do not bend. I used it for the large panels you may find in some models. I textured those with the pattern drawing so I could trace the panels. In present MD versions that is no longer necessary because you can set the pattern drawing as 2D background. The smallest curvature you can represent has a radius of about the particle distance.

I use quads for strings and ribbons. These will look wobbly when they are in tris.