Ever since I went over to dcc I never gave any real thought as to these CVs.
I generalyy upped them from their original values to CV3=8 and CV4=6, and left the TTS locos at 15 for both.
A comment from someone on youtube said they went for CV3=100 and CV4=50, which one heck of an increase.
I thought I would have a play, and set the values to CV3=50 and CV4=50, and was delighted with the added realism.
The drawback, of course, is fine control, stopping where you intend, and slow shunting work.
Do any of you use higher values, and if so, how do you overcome the other issue?