if your GT does NOT have diff tones for those items you better get it fixed! my GT will have (as all Sovereigns have) a diff tone for many items.low for Gold/pull tab/nickle lower for silver lower yet for foil,high for clad dime and so on.and nulls on Iron. iv found many dimes @ 15" on the beach,its plenty deep enough for me.the only thing iv found deeper is a PI , but you digg too much junk with them witn no discrimanation..good luck.
Now the tones on the GT or any Sovereign for a copper penny, dimes clad or silver plus the quarters and half dollars and even alum cans will be the same tone and same meter reading, The Zinc pennies the IH pennies and even some of the early wheat pennies will sound a little lower pitch and this is where a good 180 meter comes in to tell the copper and better from the zincs. From a lot of experience you may be able to tell the silver from the clads with the tones and how the meter reading will be, but it is not 100% and it takes getting to know the Sovereign well. The Sovereigns are one of the deepest and most accurate on IDing deep coins once you learn this detector as it give you the operator more info on your target and lets you decide to dig or not, not like many that just beeps and thinks it is something it feels you should dig.
I find the tones and how big a signal and how weak it is to tell the depth which also in most cases tells me it is deeper and where older coins are found. In other words if it is loud and bigger sounding I lift the coil and swing the coil and if it sounds about the same it is a large target like a alum can. Now if raising the coils and the signal gets weaker it is probably a surface target. Now if it is weaker and seems like it is very small and reads 179-180 doing the Sovereign wiggle or the tones and the meter is trying to rise it is a deeper target which is a older coin. In order to get depth you have to go slower then most detectors, you can not go too slow, but can easy go too fast and lose some depth.
If you spend the time to learn it and understand it I feel you will be impressed with what this detector can do. I dont care if it is a penny, dime quarter or silver coin if it read 179-180 on a 180 meter I will be digging, if this sounds deeper and weaker I smile a little more while digging as I figure it is a older coin.
Good luck and have some patience as it will be worth it.
Rick