I wanted to help on your post, on another forum as well. I don't own this loco and have only seen it once at a show.
I have dealt with KDs and they have a nice assortment that fits just about every app. Sometimes, I get advice from other guys on what coupler they've used. I've learned to keep an open mind. The large offset couplers that some use, will release when pulling a large train. I'm not sure you'll ever do this with the engine. I always try now to get the straight shanked couplers or the least offset, and make spacers for them that are solidly mounted and won't let the coupler dip out.
Sorry I can't help more.
I try to get the new "E" ones too, because you don't see the spring! I feel they look the best. I also try to body mount everything.
