BP,
Gotta give you a real attaboy on your man cave.
I share your pain with respect to having tools that just will not work like they should.
Tomme boy,
Some people get lucky & find 38/357 expander dies that will get the job done.
However, a lot of people try this and find that even stuff sold for the revolvers will not expand their 9mm brass enough (mine was no where near big enough).
I think there is one supplier (NOE I think) that makes expander plugs that allow you to pick the diameter. From what I have found recently, I could probably have saved myself some grief by just buying some plugs in 0.0005" increments from 0.355" up to 0.358" to let me find something that will do what I need using trial and error.
When I started, I now see that I did not have a good feel for what I needed for the brass ID after sizing, I did not have a good feel for how much "springback" to expect from the brass after expanding (varies greatly depending on maker), no clue as to how little my boolits would stretch the 9 mm cases during seating (next to nothing), and I did not realize how bad (way too much case diameter reduction) a "standard" 9 mm case sizing die was for my boolit loading needs.
In the long run it was a "learning experience" and it would seem that it ended up providing me with an "adequate excuse" to get myself a new toy (7x14 metal lathe) that I have wanted for a long time.