Sorry I don't have any pics yet, photobucket is pitching a fit right now...
Anyways... Spent a while last night tinkering/contemplating. The Kato main crank pin is a larger diameter, and longer than its Bachmann counterpart. Upon seeing the rest of the Kato valve gear, it looks great, and Since I am using GS-4 cylinders, I think I will use all of this except the main rods. All of the geometry seems to line up, I just have to figure out this pin. I think the easiest way would be to enlarge the hole in the driver, but I the Kato pin is substantially longer. It will need to be trimmed so not to interfere with anything on the backside of the driver, but I think it's doable.