The Buckeye Retriever Club is just one of many retriever clubs that train and test in the Camden Ohio area. http://www.buckeyeretrieverclub.com/
Lots of very knowledgeable and experienced folks involved with that club that would love to point you in the right direction.
"Sound like you are doing your home work. As far as chocolate's are concerned, I would be looking for some black factor ( Tilted ) within the first three generations."
Note: The chocolate gene is color only. Does not have any effect on the rest of the dog. ie. nose.
Also since black is the dominant gene all chocolates are "black factored"