Fine tuning your sonar.

[fishin' fool]

Hello all, I haven't been on the forum for a while now, just working and fishing. Caught my summers biggest about 3 weeks ago, a 4.5 pounder on a deep diving crank.
Have a couple of questions about sonars

I don't like to run my sonars on auto, I just don't think they perform the best. I like to fine tune my sensitivity to meet the situation I'm fishing. But two different magazine articles dealing with sonars, the editors suggested running sonars in the automatic setting. There theory was that the newer sonars are much better in the auto setting compared to their older models. I was wondering what if you guys run your sonars in auto or manual mode? IF you run it in manual, about what is your average sensitivity setting. I know model and fishing conditions will change it. Mine is usually in the area between 55 and 75%.

Second, since I run it in the manual mode and fish i.d. off, sometimes I don't see any fish arches. I may know or catch fish off of an area, but never read any arches on my screen. Sometimes I do get partial arches, but that is a fish not fully in the cone. I'ver never seen a ture fish arch. Any fine tuning tips to help me out? Thanks and good fishin'!