HVAC, when you say that you are going to use them "for aging," I assume you have a way to make them air tighit with a possible addition of an airlock, right? The barrels that I used were only for fermenting. I cut the top off with a saber saw, installed a spigot near the bottom and crushed my grapes right into the barrels. Once the wine fermented for 10 to 14 days, I moved the wine to oak barrels with the bung hole open. I kept the barrel filled with additional juice, which I checked a couple of times a day at least, for about 45 days when all fermentation had stopped. At that point I sealed the barrel with a wooden bung.
As far as aging in the barrels, as long as they are air tight it would seem to me like the same bulk aging that you would get from a carboy, but not from a barrel. That is, there would be no micro-oxygenation.