I'm an an air hog too. My wife is not. The weight of the 100s is non existent once you're in the water. The only time you deal with the weight is when you stand to sit on the edge for the back roll in. When I dove with Blue Magic, I would take my bcd off in the water and the Capitan pulls my gear in with me pushing from the water. I could get right at. 1 hour dives with 100 cf tank. I would surface with 500, my wife would be at 900 or over.
Some DM's will let you surface alone and will buddy up with your buddy for the rest of the dive. We did that on our last 2 dives and Kelly got well over an hour of dive time.
I believe Aldora dives steel 120's. Since they are steel you will use less weight so it may be easier. Steel tanks are kind of different to dive and try to roll you until you get the weighting figured out. I'm sure Aldora can get the weighing near perfect from the first go....Me..not so much. Lol
if you hubby can burn up a 120 while you go through an 80, he either has a hole In his lung or might benefit from a 1 on 1 session with an instructor. From weighting, to buoyancy issues, to just relaxing, some regs burn more air, and probably 100 other little things can make a difference. I'm getting better, not nowhere close to where I want to be. My favorite advice is....you just need to dive more...no problem!!
i had no issues with the 100's and the extra cost is well worth it for the extended time with my wife. (Although we actually enjoy diving more without each other because we don't have to worry about the other)
good luck and safe travels,
jay