Okay, latest update on this on-again-off-again project.
Something just wasn't right on the LH stack, so I disassemble it and roll the rod on the table. Why i didn't do this before? Haven't been in the hobby much lately, actually. Turns out the rod was significantly curved. I put it in the chuck of my craftsman 18v cordless, set the speed to high, and spin it while applying tension to the length of the rod while it's turning. After about 30 seconds, there is now no wobble as it turns.
A straight rod. Yay!
I go to fit the rod back in the horn. It won't go through! Turns out the second and third posts aren't in line with the first and the last and there are no dents that would have explained this misalignment.
No wonder the rod was bent. Nice QA there Selmer!
Okay, so I unsolder the posts and use the keys to align for distance while repositioning them. The posts are aligned now!! I just used flux and a tiny bit of solder in the one, the second I used no additional solder, but I consider this an okay job.
Unfortunately, there is too much play in the B key now, so I bought a swedging plier from Musicmedic.
ah well, I wanted to get more tools anyway...