So I am in my third year doing a 5 gallon oak barrel Solera project. I added some tart cherry wine base to my barrel last winter and popped in the whole cherries on some left over Flanders that was in a glass carboy and hit it with another pack of Brett Brux. Wow, what a tart bomb. So, I blended the wood aged (half gallon) with the tart bomb (about a gallon) and about 3 and a half gallons of fresh Flanders Red (from January). Pretty light and restrained - much more balanced.
Happy with the results for just a wild stab in the dark. I think I may wrap the barrel in plastic food wrap to keep it from evaporating so much. Otherwise, I will soon be on to a summer Flanders for fall mixing.