pasttom said:
You did ask for opinions so...
The 'PRO' coil that you have is a darn fine coil. The ones you are looking at are maybe a tiny bit better in some areas. I think you'd be better off getting used to it and hunting for a couple months, then deciding what if any coil might do you better.
This is a do as I say not as I do suggestion.
I absolutely agree with Tom here. I'd love to steer you toward a big "this" or "that" but unless you have maxxed out your current coils capabilities in the places you hunt,I'd do just as he suggested and use the Pro coil to its fullest. Make sure you are OVERLAPPING RELIGIOUSLY! This is really the key,to get as much THOROUGH coverage of the ground possible,and from a few different angles throughout a site until you are satisfied you've done your best with what you have. Depending on WHAT you're hunting,there is NO reason to run with the screen wide open. Some will disagree and that's fine,there are different styles of hunting. Set your discrimination according to what you want to find,plus a bit. The machine knows what it's doing. Don't over-think it,swing thoroughly,coil on the grass and advance slowly. The coil you have is likely capable of much more than you know.
When you're all done with that,then a larger coil will get you more depth. For me,larger coils ID those targets better that were on the fringe of the stock coils depth. They can both "see" the target,the big coil just sees it better. There are of course the super deep targets only the larger coils will see clearly enough for you to investigate the signal.
This morning,with my CTX running the 13" wide coil,I hit a well worn 1920 Mercury dime in the same hole with a rusty 8 penny nail. Signal was a solid 12-46 with a distinct "clunk" in the audio. Both items were past 9" in thick black dirt. Even while that is a good find,I have no doubt the eTrac or my Explorer2 with the Pro coil would have also hit the targets and given me good enough ID to dig. While I do NOT own an eTrac,my Explorer2 also has an uncanny knack for deep coins,at relatively low sensitivity settings(18-22 manual).
Set the machine up so it's got a good stable threshold for whatever site you're in...go hunt.