I previously posted similar for another who WTT w/.45
38 was the most common caliber and 9mm was much rarer in quantity, and less common, the value is different and I doubt you will find many people willing to trade straight up, but maybe open to trade and cash as you suggest,
I know Rich Daniels (Barreltester) on this site make shell-plates, but I would also expect Bruce Williams (RBWillNJ) on this site, can supply both dies and plate and get you up and running in no time.
FYI
When I began to load .9mm, I went with an adjustable measure until I found my ideal load and then drilled a bar to that fixed powder drop.
Good luck!.