I always use momentum numbers that make the loco perform like it has full scale mass. Using the following momentu numbers also alters the sounds of the prime mover as it sounds like it's really working. i.e. running light to pulling a heavy load. ***Caution*** using high values for CV4 and CV24 will dramatically increase braking distances.
CV 23 = 40
CV 24 = 127
CV 3 = 0 for running light (add 5 points for each passenger car)
CV 4 = 150 - 200 depending on load
Give these a try and see if it's like the full scale.