Thanks for the quick reply, Dan
I too have that service manual and also rechecked that snap ring position. Isn't that the same snap ring that integrates with the end spacer that holds the clutch drive in place (from flying off the armature shaft)? It's on the second notch down from the end of the shaft.

Seems like I'm missing some other important spacer part that keeps the shaft down into the lower bushing, 'cause right now it's floating whenever it's energized. This might also be causing the drive/pinion from not reaching its max throw for full flywheel engagement ??