OK, I can tell you for sure that ADF Sender Terminal (
http://adfsender.stoeggl.com/ ) running under WINE in Linux works for transferring floppies to the Amiga who was running transwarp.
I just installed it (I chose the ZIP package, unzipped and ran the installer with WINE), chose COM1 19,200.
I told the Amiga : transwarp -w ser: -b 19200
I hit enter. Went to the PC, selected the image of Firepower I DLd. And it started transferring.
Several ... several ... several minutes later (It is serial! :-), it was done. Rebooted, and Firepower started...
The fastest I was able to transfer on my Amiga 500 safely was 19,200. (The laptop I was using had this REALLY old USB-serial port adapter. I think you're supposed to be able to get to 38,400 with a standard A500.
I'll have to see how fast I can transfer to the A1200....
desiv