Hi Charles. I will try to relate to you what I know.
I prospect for gold nuggets. I used to have a Whites DI Pro but could not find the time to use it so let it go. I started nugget hunting with a Whites Gold Master VSAT. It is a VLF type detector and designed for finding gold. I have found nuggets just over 1/2 oz. with it and some so small they will not be considered as a nugget but a speck. I once found a screw out of someones eyeglasses. This type of detector has a average depth range of up to 6 or 7 inches, depending on the soil conditions. My main detector I use now is a Minelab GP Extreme. It is a PI type unit and is for serious hunters. While it has draw backs such as battery weight, cords and such, the ability of this maching to punch down deep is worth it for me. It has a wide range of coils available for it and more comming out every day. 1/2 oz. nuggets at 2 feet are not uncommon. This maching loves mineralized soil.
As far as your machines, I have no experience with those types. They are VLF types so I would expect that they would act like my DI Pro and they will find gold but not small gold. You would probably find a 1/2 dwt. nugget around 2 or 3 inches depending ground mineralization. Try to get hold of a gold ear ring, the one that looks like a little round ball bearing, as a test target, it will not be much different than a gold nugget. Hope this helps.
Micheal