Awesome. So as long as I have a 68mm BB shell, and a 73mm crank, I should have a bit of room for manouvre for a wider chainline? Thanks, that makes sense.
Did you go for a double, or a triple and just use the outer rings? The build that I'm emulating has an inside chainring stuck on the outside of the crank, which narrowed the gap between the 2 chainlines. Did you get up to similar witchcraft? `Not sure if the same game can be played with MTB parts. I've had a look at chainrings, I think I can get what I need, ratio-wise. The only truvative chranks I can find are 175mm, but cheaps, so I will probably venture down that path.
More searching needed. My poor computer is struggling with my feeble google skills and clueless crankset knowledge. I had over 70 tabs open on my browser earlier, a clear sign that I have as good a grasp on this as Peter O'Hanraha-Hanrahan has on political journalism.
The hunt continues...