hey check this out, i'm in a similar situation. maybe this can add to your bag of thoughts on the matter.
i have a conversion with the following specks:
120mm rear spacing, 68mm bb shell, shimano 105 crankset with 110mm jis bb, 120mm hub w/freewheel.
this was set up with advice from my lbs. i want to get a kilo tt and move everything over. but i was also concerned about bottom bracket spindle lenght, as you said the kilo tt comes with a 113mm.
i was told that since the frame and the bb spacing were identical, the bb and crank should port over just fine and the chainline would be pretty much the same. granted,i haven't yet done this, but that is what i was told.
i think the spindle lenght is related to how the crank mounts to the bb. which might be why a shimano 105 uses a 110mm but the truvative must use a 113mm in the same frame.
thoughts? helpful? fail? lol!