I met up with a local guy (Dallas) last week who fabricated an OWB holster for the USP .45C w/ tac light. It's .060, 0 degrees, w/ 1.5" belt loops. He assured me .060 would be more than enough to hold securely and so far, it appears as though he is correct. Only time will tell.
I've got the first one but you're going to need to send over the last two if we're going to make this work.