I put an SA XRD-5 on my daily commuter spreading it out 5 mm on each side to 130. It took a while to iron out the new chain line but other than that, there was no apparent effect on the position of my panniers. The compatibility with your SS wheels is your big issue and I don't think you will ever satisfactorily resolve it if you spread your frame. My suggestion is to drop the idea of a 5 speed and buy a 3 speed 120 OLD hub. This is what I wish I had done in the first place and am now strongly considering reverting to. The hills in our area are not all that challenging and I find that I almost never use any gears but the middle 3.