One thing is for certain, don't ever try to do that HERE!
The White's (their main plant is 1 mile from here) have cleaned out just about EVERYTHING, except for what the old Compasses and Fishers locate now and then, because the Fishers and Compasses go a bit deeper and handle bad ground better than anything else on the market, used or new. I haven't seen a Minelab within 50 miles of me exept for my own in all my years of detecting here, and the only Garretts I've seen are either in pawn shops for sale cheap orthe one I owned for a short while. I see a Minelab on the beach sometimes but usually they're fooling all the time with the settings and not hunting. I don't even see Tesoros any more around here. I have seen more old Compasses than I would have ever imagined. Whites, Fishers and Compasses are the best things happening here, and without them it would really suck.
And the reason for all the above is because quite frankly, most Minelabs, Tesoros and Garretts don't work as well in this real nasty soil here and don't (or can't) completely ground balance well here, including the infamous Minelabs which electronically try to chose one good search freq out of many at any one given time.
In fact, I just exchanged with a lady (on this site) who wants to detect with me, who owns a Tesoro Cortez and a Garrett Ace 250, and she has the same problem with both detectors, just like I do with my Tejon and the Ace 250 I owned and gave to my daughter. Those two can't deal with this nasty soil. The Tejon and the Cortez only GB to within 2" of the ground, and then they would howl as I lower them further. The Ace 250 just makes a lot of noise yelling at everything before it's finally putback in the truck, in disgust. I could switch the pot on the GB in my Tejon, but I think I'll sell it instead. The cheaper, less powerful Tesoros do a lot better here than the high end ones here, and that's where the ball stops too.
Don't try it here. This is NOT a good place to retire for metal detecting, but Great Britain is. It's a detecting bonanza there.