How much more depth do you need, and what is it worth to you to get it?
I assume a bigger aftermarket coil will get you some extra depth, but you might have to deal with extra emi or other things too so it may be a wash.
Your soil is pretty sandy so I am thinking the F5 and 11" should get pretty deep, also that Pro.
The F70 can get crazy deep, but you get the best depth with the 11" DD coil over the standard elliptical so keep that in mind.
I have seen the F70 and that big coil in the classifieds for $500 and under once in awhile.
It can be chatty and especially at high power setting but that is just part of the language, it will tell you when you are swinging over something good no matter what if you know the language.
If you want quiet turn it down...still gets surprisingly deep.
Experimenting I picked up a solid, repeatable dime at 5" at a sense level of 19 out of 100...1/5 the power possible.
Imagine what it can do if you turn it up.
If money is an issue, and you are hot to trot to get deeper immediately, AND you become educated enough to be sure you will get what you need with that new accessory...get the coil.
When I add big coils my detectors feel new to me, and the extra depth is always welcomed.
If you really are crazy about super depth, an F70 o r F75 will still probably be in your future one day anyway.
