Dave,
Do you think that aging the new barrel in only a small amount of bourbon would impart enough of a bourbon flavor into the barrel? Obviously the most important part of that would be consistently rolling the barrel. I'd also be concerned that the new staves wouldn't swell consistently as well. I like this idea though. It would save us a ton of money to not fill this new barrel entirely with bourbon but only use a smaller amount. It's really the only reason I didn't go up to a 5 gal barrel. This may be the way I go about aging my syrup this year.
Thanks for you knowledge,
Dale