@tanza Thanks for your thoughts. Aten is a dog's dog, was well socialized as a pup and really plays well with other dogs and very rarely nips. When he does, he of course is just trying to initiate chase.
I've worked with him for the past 2 weeks on recall and attention, and he is back to being the rare basenji that behaves. I still need to pay attention, but if you're not, you don't belong in a dog park, right? (Our park does not have large and small "sides".)
Given Aten's love of dog play, and the insanely close proximity of this dog park to our home it's something we'd rather fix than forego. He's never injured another dog, just scared wimpy ones.
Thanks again for your insights! Stay well!