Trick or tool to help line up 48 splined crank arms Besides eyeballing it and comparing the line to the seat tube, are there any tricks to getting 48 splined crank arms perfectly aligned? I must have spent a solid 15 minutes looking at them from every angle until I was satisfied.
If your bearings are decent, just take the non-drive pedal off and let the pedal weight pull the other side down, or slowly let it fall from slightly off center. This is how I could tell with my Bullseye cranks, besides hopping on and trying to pedal it. If that doesn't work then I'd try tying a heavy weight or looping a paint can around one of the pedals close to the crank. 

You're looking for a 7.5 degree distance, so on 185mm cranks that's 24mm or nearly and inch of diference between splines. Weighting the opposite side enough should make it clear. I then took some nail polish and marked both the crank and axle so I didn't have to play this game again.