These are all great-running locos in the eyes of prewar collectors. I'm 99% sure the 763e Hudson requires O-72 curves, although it has a blind center driver. Even if it would take sharper than O-72 curves, I wouldn't do it; the drivers on that loco are fragile. Also, the frame on the 763e is prone to warping. You might not see it when you look at it, but if the frame is even slightly warped, performance will be an issue.
Also, regarding color, the only one of these locos that was not produced in gunmetal is the 226E--it was black only. Gunmetal loco/tender combos with the coal tender are going to command a much higher price than the other tender types.
John
