Hi Sandtiger Steve,
First of all, from what I've heard, "skip-breathing" (or breath-wait-breath-wait) actually carries with it the risk of hypercapnia (buildup of CO2) which leads to hyperventilation...something that will certainly *not* be good for air consumption.
It's also not generally considered a wise idea.
Alright, that said it is part of my job to be an "idea person", so all I ask is that you open-mindedly put these ideas up for consideration, and go from there...
1) You may want to have someone tell you if you're pointed "nose down" while diving the majority of the time. This position tends to make your cardiopulmonary system hoard more CO2, and can lead to excessive breathing.
2) It *may* be worth it to have a medical cardiopulmonary stress test. It will give you metrics (and a starting point) on where your current consumption under stress (and not under stress) begin. This, of course, has a hefty expense associated with it, so it might be something you should have your general practitioner refer you for...if not, a friend of mine's quote comes to mind, "We spend thousands of dollars on our cars each year for diagnostics and repair, but we cringe when asked to pay for something as basic as a stress test for our own bodies"...Obviously, this is up to you.
An easy test though is a "lung capacity test" which I think you can do with little more than a straw and a stopwatch (if what I recall from high-school science class still stands).
3) Yoga - excellent source of relaxation. You may also consider some martial arts (Tai Chi is most likely a good candidate, but others work as well) specifically emphasizing the need to breath and relax. When you can breath calmly in a sparring situation, you'll be as calm as you ever will in diving.
4) There are a number of breathing and relaxation techniques out there ranging from visualizing the colors of the rainbow in order while relaxing specific parts of your body, to simply thinking about it consciously. Regardless, being totally stress free and relaxed will have a dramatic impact on your SAC. After you're prepped, clear your head before the dive and start your breathing exercises...it may be useful. Any leakage in your mask that is abnormal may be a sign of pent up, and unaddressed stress, so be keen on this and other similar things (buoyancy tweaking, facial expressions, etc.).
5) Obviously, smoking and sheer body mass are contributing factors to air-consumption. That's enough on that topic.
6) You should consider buying your regulators...for safety reasons (used to the equipment) and because you can practice with it more and tune the system to your individual needs.
7) Not very realistic, but living at altitude will increase the number of red blood cells in your system, and allow you to breath less frequently at lower altitudes (such as sea level and below). Those of us that live at altitude (and I am fortunate enough to be one of those folks) have a *very* slight advantage when diving in the ocean.
The bottom line though is you'll want to tune the overall situation, equipment, and your body to meet your diving needs, never be concerned about being the guy to call the dive, and find a buddy who is roughly at your SAC rate. Whether you spend 30 minutes or 2 hours underwater, you'll still be underwater (that's kinda the point, isn't it?).
Good luck, and Enjoy kicking up those bubbles!
-S
