The TPS in the carburetor is working fine. I found +5V for it and it's giving a nice signal of about 0.65V to around 4.50V. The problem is that at the other end it's too high for the AXE controller and at the other too low. With the best custom throttle curve map I found online I get 6% minimum and 80% maximum throttle. So it's a bit of mixed bag. It works, but not prefectly. I've sent an email or two to Alltrax and hopefully they'll be able to help me out.
If anyone else has a tool for making hex-format maps for AXE 7245, do throw me an email.