Youre gonna get much, much more of an effect from angling it. The bass will be bassier and less tight, the treble will be brighter, because of what part of the string they will be under. Its a pretty significant effect and should be avoided unless thats exactly what you want (like hendrix sounds for example, thats a big part of his strat tone).
Using a wider spacing, as jonathon says, wont have any effect (at least no perceptible one). Think about it - when you bend a string youre moving inbetween poles there, and the tone doesnt change, so having a couple of mil surplus to the width wont have any more effect.
