I use the 93sv chirp unit. I find that using a blue bckgrnd on 2d shows everything well and less is likely to show interfence (should you have any) quite as much as the white. On sv and dv I use the inverse gray pallette color mostly. Seems to work best/better in more conditions for me. I run my gain up just a bit, contrast I leave at default. Scroll speed toward the faster side slightly. Default settings work pretty darn good, but any unit can be optimized by tweaking a few things. Just do it one at a time, return if you don't see what you want. Stop fishing long enough to go over some known areas and play with it until you are happy. Keep in mind conditions change, and it does effect readings. Record some of your trips on your micro sd card and replay on the HomePort thru Garmin on your computer. You can make a lot of adjustments there while at home. Helped me. Talk to techs. They are very sharp, nice and someone is always there within about four rings.
This is a post from TeeDee froma earlier thread ans i set my unit up using this advice and adjusted to my personal preferences while I fished. I think i like the green better on downscan but the blie on the sonar is the best.