Welcome to the forum
I'm afraid there is no best setting that is going to guarantee you hammered coins .
You're best bet is to do some intensive research of your local area and get permission to detect on land that has seen habitation for the past 2000+ years.
Just look at the recent Weekend Wanderers 3x day rally held last weekend. There were over 1200 detectorists there for 3x days and I haven't heard yet of a single hammered coin found on hundreds of acres! what does that tell you ?
Personally I would suggest that you use the maximum amount of sensitivity you can before the machine goes unstable . Depending on the ground you are detecting on that could be as high as 2x notches from maximum.
I don't recommend searching in all metal mode for the novice using any of the Garrett Ace series.Its just too damm noisy!. The cacophony of sound you hear on most land will deafen and confuse you.
Don't use the 'coin' mode either because the notch that is missing from the middle (ring pulls ) also is exactly where the majority of hammered silver coins are .!
Some experienced Ace users say using all-metal mode you get a possible increase in depth of 1/2" or so...... well zippadeedodah
I'll trade a 1/2" for a more pleasant and easier learning experience anyday .
Use the descrimination .....thats what its there for !
My recommendation would be to put it into 'custom' mode and notch out the first 5x notches from the left ....that way you won't spend all day digging lumps of iron and rusty nails and get fed up and dissillusioned as you sound now.
Try and borrow some Roman And Hammered silver coins to try with your detector so you can see where the signals come on your lcd screen but more importantly you can hear what the tones sound like.
Go and hit the local library and do some research on the old maps of your area , good luck
