I completely missed the point that the G scale diesel was 1:32 not 1:48. That's why I like to post this stuff, gets more eyes looking at it. Thanks.
I'm guessing that the Scale Factor, the Speed Factor and the Chuff Factor are all based on wheel diameter, tach stripe count and gear ratio. Then Scale Factor adjusts the DTO and DOD counters while Speed Factor adjusts the motor speed. And Chuff Factor adjusts the smoke fan.