I agree it's usually best to model clothing around the base OBJ file rather than an exported one; but in this case, Tyler is a morph. 

I would suggest this .. if the intent is to model the clothing ONLY for Tyler, then the only choice is to export the Tyler morph from Poser, being very careful not to include any rotations or translations before doing so.

However, if the intent is to also include support for the other body morphs in the clothing, then your best bet will be to model the clothing around the base shape (the original OBJ file) and then add the Tyler morph, along with the other body morphs you want to support, into the base clothing.