The slow retune lower VSAT setting is better for smaller, deeper nuggets, but just like Willy said, sometimes you have to have it set high just to wade through all the hot rocks and cold stones. If you ever get a chance try the GMT, Ithink that for nugget hunting it's better than the MXT. I borrowed an MXT from a friend of mine, and found that the ground tracking, and the iron probability were much better on the GMT. Though, I do think the VDI feature is a nice information to have.