Nick -
Heartfelt thanks for taking the time to give me thorough practical advice and for steering me to those service instructions. Without those it would have been a disaster. It may still be, but I'll get closer.
The Marx axles are 0.134", so at least I'm catching a break there; I won't have to turn down the wheel-puller's pin. I looked at those elbow lumps on the Grossman's puller when I first saw the pic, and wondered if they could get into a tight place.
-- D