I'm not sure you even need a tank. That tank is not big enough to fill even one tire, so it will only save you a couple of minute of inflation time for one tire. For your projected use I would just get a decent compressor...even a Superflow MV-50 would do a great job for you for only around $60. I have used one for years, even with my 35" tires.

A CO2 system holds MUCH more volume per tank/bottle, because the CO2 is stored in liquid form. You could probably go a year or more with a 10 lb. bottle based on your projected use. BUT, the CO2 tank must be stored upright, which may not an option for your storage space.

If you are interested I am putting a CO2 system together, I have a 20 lb. bottle, a fire extinguisher bracket, a fixed-pressure high-flow regulator, and a good coiled hose that can handle the cold temps of the CO2. Just need to get it mounted safely...definitely don't want that tank crashing around the vehicle while wheeling, or in the event of a rollover.

There are also commercial CO2 setups available, such as the Powertank...they are pretty spendy though for a thrifty Scandinavian like me.