You really want to run it pretty wide open. It's pretty simple, Load up the beach program, then switch to Quick Mask, black out only the bottom 2 bars and start hunting. Just say NO when the E-Trac asks you if you want to load that Quick Mask setting as your pattern. That way, if you want, you can hit the Detect button and go back to the stock beach program if there is too much iron and trash. In that Quick Mask setting, you will be in Conductive Mode, with multi tones, but you will hear most all targets except small iron. Still look for the prime ferrous/conductive combos like 12-45, 12-14 or 12-15, but in salt water, and with iron around, don't pass up 06-10's and such that sound good. I dug a few deep nickels that were in that range. Dig all those lower and mid tone targets as well as the highs that sound good and repeat when sweeping at multiple angles. You may get fooled by a few rusty iron targets, but be aware of the tone and how the numbers/cross hair icon bounce around. Most iron like that will not target in a set range and be all over the place when you investigate it via sweeping from different angles.
One thing to make sure of...run your sensitivity on manual, and in the 22-24 range if you can. Don't go into auto unless the conditions make you. You can mess with the other settings, but to keep it simple, that is the way I would start.
I only have had my E-Trac for about a month ( but have been beach hunting a long time), and have not even scratched the surface on how to tweak it, but the set up described above is what I have used the last time out on a beach in NJ and it worked very, very well.