I am about to pull the trigger on a craigslist find. The ad claims a 7 gal and 5 gal carboy for winemaking. I assume the carboy on the left is the 7gal. Would this shape be ok for a primary? I'm concerned the shape might shoot krausen out the top. I am also concerned that the surface of the liquid will be greater due to the shape and increase the chances of oxygenation.