Update: So I cut some hulls to 2.53" or so. Ran a few empties through it and lo and behold, the gun operated and they ejected OK. So I loaded some up using card wads and wax to seal the ends up for now.
I hope to fire those this week. My thought is to eventually use hulls cut to the shorter length and use a roll crimper with cards for a better result. I'll report back. I'm sure many of you are in suspense....