well, don't count on a steel 80 for starters... most of the shops rent aluminium tanks around here.
Some shops (like Maui Dreams) do have AL100's for rent in limited quantities.
Keep in mind that a tank's actual contents depend on it being filled to working pressure -- i.e. an HP100 filled to the working pressure of 4000psi will contain the same amount of breathing gas as an AL100 filled to the working pressure of 3000psi.
Maui Dreams uses a 3-filter system that is a step beyond what is needed... something that most shops here don't do. They can also fill Nitrox to whatever blend you want, without using PP (they have "The Stick").
Rather than "warm water" it'll likely be the shallow depths of the shore dive sites here that makes a tank last longer... but if you want to compare, download your Vyper and punch in your starting & ending PSI into the SDM. It'll tell you your SAC that you can compare around here -- I run anywhere from a 0.4 to a 0.65, depending on stressors, and get 45 minutes to an hour and forty-five on an AL80 at our shore dive sites.