Phog, it wasn't so much the axle diameter I was referring to, rather it was the flange that the pulley mounts to. I know with some of the Softail spoke wheels that flange on a Softail is usually a little longer then one we find on a Dyna, I wanna say about a quarter inch longer or so. I wasn't sure if this applied to mag hubs as well or if maybe the Deuce's rear swing arm in narrower or longer axle spacers.
Yellow arrows show flange that is usually the same, the red arrows show the different flange lengths.