Don, maybe you could post a video of how your loco runs with the stock electronics, once it has a little break-in time. I was personally never impressed with TMCC1. Setting the "stall" speed helped make best use of the 32 speed steps that were available, but the vagueness of the CAB-1's big red knob made for more "remote" and less control.
If you're lucky enough to have a CAB-2, using an ERR AC Commander in R100 mode should give you better control. Ultimate performance will depend a lot on how well-sorted your drivetrain is mechanically. I'm a big believer in optimizing the mechanical system FIRST before throwing electronics at it and hoping for a miracle. Good luck, and I look forward to that video after she's had some track time!
