2013 Kona Jake, 2008 Kona Major Jake, 2013 Kona Jake the Snake, 1999 Kona Muni Mula, 2012 Ridley Excalibur, 2008 Surly Long Haul Trucker
Have you tried asking the in the Mechanics forum? I don't know a lot about Octalink. Is that one of the standards where the axle length is theoretically paired with the number of chainrings to give you a standard chainline?
In general, given the expected spindle length for a crank, it's easy to calculate the change in chainline that you'd get from a different length bottom bracket. The chainline for a double is the point between the rings, while the chainline for a triple is the location of the middle ring. Generally, you don't want the inner ring to far in, but with a triple, it's good to have the outer ring farther out.
With standard chainlines (43.5/45) and a typical 5 mm spacing between rings, the inner ring is at 41 mm for a double and 40 mm for a triple while the outer ring is at 46 mm for a double and 50 mm for a triple. This is the consensus standard and seems good for most people. Depending on your typical usage, you might be able to get away with some variation.