This comic uses FV5 but hair length stays the same, btw, which I think I decided is FV4? Not sure. Gonna call it that in this commentary, however.
I didn't just choose these examples because "ha ha, the two girlfriends with parallels to each other who were both interested in people who look almost identical assume their forms".
Thing was, I wanted to show that the end result would be effectively identical, but I also wanted more variation between examples. By having Rhoda / Catalina -> Susan / Diane for examples, I got to have my cake and eat it, too.
In any case, the important thing is that (Paste + Beam) = (Beam + Paste), the only difference being that how clothes wind up fitting could be affected. Paste doesn't resize clothing, so if a beam spell resizes clothing, whether it's first or second could matter in that regard.