One thing I used in the past to make patches for flight suit is to remove all alpha masks and slapp a “texture finder” (usually a texture made of coloured squares with numbers in them*) on the patch file.
This gives me an idea of the UV mapping for said patch texture.
Having colours and numbers allow you to pinpoint very precisely the place where you want your patch to be.
Hope I was clear. 
*Like so
or so
and that gives you stuff like this
