I agree to find the majority of gold you need to dig in the foil range but you can indeed increase your odds with just a few changes.
What's the difference between a detector with 199 target ID segments and a detector with 20 target ID segments? Being able to more precisely ID gold over foil. In tot lots I rely on the AT Pro's great gold sensitivity, but in those parks and school yards it is about target ID variance. If you've only got 20 target ID segments a whole lot of foil is going to read like gold would. You would not see the VDI variance you'd see with a detector that has 199 segments. I used a White's DFX for 10 years not because of depth, but because it's ability to more clearly show the variance in targets. Especially gold and foil.
Take a piece of gum wrapper foil and you'd probably get a 39-40 from any angle on a detector with only 12-20 target ID segments. Same as you might get from a gold pendent, small open earring or chain. That same piece of foil on a detector with 199 segments will vary greatly, unless the foil is round, from 35-44. On a detector with 199 segments that gold will not vary unless deep. Of course this isn't 100% but it does increase the odds in your favor and isn't that the name of the game?
I now use the MXT All Pro because it not only has plenty of segments, I believe 198, but it is a bit deeper than the DFX in my soil.