Okay, so if your estimate of your stock offset is correct (sounds right), your new wheels will fit 2mm more inboard. Good to know.

Where on the splash guard are you rubbing and with what part of the tire? For example: Inside edge of the splash guard toward the top, front tires, scuffing the sidewall. Or top of the splash guard, front tires, scuffing the outside half of the tread.

Knowing exactly where you're rubbing now will help determine whether your new tires will rub.

I'm still thinking that unless you want to bump the ride height up (which would probably be a good idea... if you're low enough to rub 185's, you're probably on the bump stops which isn't good for handling... been there, done that) that 195's are what you should get.