I have a stock Truvativ Touro 50/36 compact crankset with a 68x108mm BB and a 45.5mm chainline (?). Pretty much an outdated square tapered crankset. And a 12-26T 9-speed cassette in back. I'm leaning towards a 34T x 11-32T setup.

The BB needs to be replaced and my options seem limited. I found a Shimano UN54 BB in 2 potential sizes. Reviews seem pretty good and they are cheap.

I'm trying to get the straightest chainline for this setup. Should I get a 68x107mm and run the chainring on the outside (I'm adding 2 bashguards) or get the 68x113mm and run the chainring on the inside?

Is there something I'm missing? This is all new to me. I'll appreciate your comments and/or expertise.