Dawn is closer to V3 than to V4. The fitting room does a good job with fits and conversion of morphs. 

I add a rough posefile to get started.

Load Dawn, Load a V3 conforming clothing, do not conform the clothing but aply the pose to it. Tweak if necessary (the fit of the arms looks horrible but works) In the pose room make a new fit, do not zero the clothing, but zero Dawn, and fit fit.

No guarantee whatsoever, but it works for me.