Can't help you with the BH pioneer 101, except to say that if you want jewelry and coins, better set the disc. to accept all conductors. Gold jewelry can read down to foil wads. So get some foil wad samples and air test them. If your disc.is high enough to knock them out, then you can miss some gold rings, especially smaller ones.
As for the hunt site, if there was just a single race there in a field, a single time, then there may not be a lot of targets. Typically speaking, you want to go to places where people gathered time after time, year after year. Not just a single random event here and there. The more people that gathered, more frequently, for longer periods of years, will lend itself to more losses build-ups. Also a race site may not be to conducive to jewelry losses to begin with. The best places for jewelry are swimming beaches where people get in and out of the water, frolick around with slippery suntan lotion, playing sports, etc.....