Looks like you're on the right track. I have a hard time measuring with all the stuff in the way, but when I put one end of my calipers on the middle ring, set them to 45 mm, and went as straight as I could up to the BB, it looked a fair bit closer to the drive side chainstay than the others. Assuming they're parallel, (I couldn't get my calipers in there to find the midpoint) I need to go with a shorter spindle. I'd have thought that going from 115 (recommended) to 110 (on their now) would be enough to correct for going from a 135 mm hub (FD and crankset are 8 speed Deore LX, so I'd assume designed for mtb hubs) to the 130 that's on their now (rear triangle is actually 128), but maybe going down to 107 will help. There is definitely room when the chain is on the little ring, where it's probably got 5-8 mm before it would contact the stay.