I think it is unfortunate that the operators who dive the Vandy regularly don't offer meaningfully larger tanks. Captain's Corner only offers AL80s and short-filled AL100s, which give you maybe 90-95 cf depending on the day. If memory serves, DKW has steel 100s, which would be an improvement albeit a slight one.
Between the depth, the current, and the fact that the most sensible dive plans involve following a circular route, it is easy to have a sensible dive plan that has to be scrapped 1/3 of the way through because someone is low on air. That's demoralizing for everyone involved, and poses safety risks if someone misreads their SPG or isn't watching it or lies or whatever.