I have this one for agitation. I like it because I can just slip it over the dogs head and snap the two snaps. I don't have to fight to get a dogs leg through or anything.
Padded Double Ultra Leather Quick Release Dog Harness - $84.95 : Dog Equipment, Police Dog, Schutzhund, Service Dog, Dog Agility
I don't use a harness for tracking. I'm sure you can use the same one for both if you wanted.