Is it best to pose the model and then do UV’s or should I do the uv’s first then pose or does it even matter in zbrush? I might be bringing my work into another 3d app for rendering - not sure.
UV’s will always deform when deforming a mesh. So it all depends on what you want to do with your mesh. If it is just going to be used in a single render then you can unwrap after you pose to avoid any distortion.