Spoiler inform: there isn't any universal ‘greatest metal detector for gold’. (Even though the GPZ 7000 is close for people of you who can afford a detector that’s the exact same value as a car or truck). The MINELAB Gold Monster 1000 at 45kHz represents the gold standard for sensitivity, https://www.lycantic.com/forum/viewtopic.php?f=2&t=1612793