If you want to use a Campagnolo crankarm with a triple-izer, and you want the front chainrings to be centered on the rear cluster, then you should be looking for a spindle that will move the crank over about 2.5 mm, half the spacing between a double set of chainrings. That's 5 mm longer in the spindle than a double would require, assuming that any L/R offset is the same. Sutherland's has a useful measurement for BBs in this respect, the "shell-to-end, right" or SER dimension. I don't know why manufacturers don't publish this, for the convenience of mechanics and other wrenchers trying to do just this sort of thing. Sure, manufacturing tolerances and differences in the taper end size have an effect on where the crank ends up too -- but it would be helpful as a starting place for comparing different BBs.

If you want to use a Phil, find out what spindle length they'd recommend for your crank as a double, and add 5 mm to it. With the adjustment that BB provides, you'll be able to hit it right on.