I like running IM 22, for my "pattern." Most targets, even DEEP ones whose FE numbers tend to creep higher-than-normal, tend to hit below "22" on the FE number, so essentially this "pattern" is one where I "hear it all" except for iron. You will dig alot of trash, at first, but in time, this is a good way to run (IM 22) in my opinion, so as to "not miss" the deeper, often higher FE-number targets.
I like to run variability maxed at "10" and the same with "limits" (so as to utilize the maximum number of tones and thus learn the tonal nuances that exist for each different type of target). I run sensitivity in manual most of the time, as high as I can run without falsing becoming extreme -- often around 26 or 28 is about right, but soil conditions (moisture and mineralization) and site trash density will dictate. Occasionally, in VERY wet ground, with a TON of iron/nails, I will run semi-auto sensitivity, but not often. You might try semi-auto at first, as it will be a smoother/quieter hunt for you. I like gain at "8" -- which allows deeper targets to sound a bit quieter (and many iron falses to sound REALLY quiet); assuming your hearing is good and you have good headphones, I find that even a deep coin still sounds clear/distinct at this gain setting.
Hope this helps some, congrats on the new machine. Coming from an E-Trac, I think you'll have a shorter learning curve than normal for the Explorer, and that you'll like it alot.
Happy hunting,
Steve