You know, Black walnut trees also make great table syrup too- tap them/cook into syrup like you would maple. My 81 year old grandma would give it to us kids on our pancakes....dangerous stuff. Alcohol is lethal to mammals in quantity too. Good thing the TTB ensures that we put it on the labels so people can avoid it. Just kidding, but I'm having a hard time finding any scientific backing of why walnut staves are a bad choice for use as a flavoring compound. I don't believe people will be inserting it into their intraperitoneal cavities, or injecting it intravenously. The only findings are an indication of somnolence. The FDA surprisingly finds alcohol to cause somnolence (drowsiness) also. Lucky for you and me, there is probably no way we will get laminitis and founder. All scientific arguments aside, it's important to test, to look for something unique, tasty, and different, to find old traditions and make new ones. That is what craft distilling is all about. Traditional bourbon was being made (and made well) long before you or I ever fired up our stills and although there is always room for improvement, there is also room for finding the new. The TTB requires charred oak to give the predominant flavor that is consistent with "whisky". As it is, I'm not making black walnut barrels, but using oak barrels with a black walnut inserts and it is a test, not a shelf ready product. Exactly what are you making anyways that probably can't be made better and more consistently in Kentucky? Are you up and running? Do you have anything on the shelf? Is it selling?
Nuff said- You should go to work for Budweiser. That should be within your comfort zone of tradition.