These are the settings I use in my MT-AIO APRS tracker from Byonics. They work for me and how I use the tracker. Your needs may be different. The .TT3 settings file for use with the programming software can be downloaded from the link below.

These the primary settings (right switch position):

These are the secondary settings (left switch position):

Lately I've been driving around with it using the secondary settings above. Here's a good track to look at to see how these settings worked on a recent trip: http://aprs.fi/?call=KD7LRJ-6&dt=1236988800&mt=m&z=11&timerange=3600

No, I didn't lose any $ at the race track, two of my sons were attending a driving course: http://www.driversedge.com