I'm an air hog as well...big guy, big lungs, and all that. I even bought my wife a longer octo hose so I can get on her "Hose of Shame" so it's more comfortable for both of us. About 5 years ago, we started diving with an op that uses the steel hp 120 tanks. That made it much more enjoyable for everyone around. Even when I would upgrade to the AL 100 tanks, it didn't seem to make that much difference. The steel 120's give us 90 minute dives. She dives a HP100 and it usually works out perfect now. If we start deep and stay deep, I may need her hose for 10 minutes or so just to extend the dive before going back on mine for the ascent. I believe the three ops using the steel 120's are Aldora (our choice), Living Underwater, and Liquid Blue. Unless your married to your dive op, which I completely understand, you might give the big tanks a try.
Good luck, safe travels,
Jay
I know Aldora has their own filling station. So they I think actually fill their 120 to the correct operating pressures. As for the rest, I would assume they use MerryD and get 3000 only. Still more though.