IMHO I would recommend using Nitrogen over CO2, it's dryer, larger molecules, and won't change pressure when hot. The cylinders hold 2100 PSI VS. 1000 or so with CO2, thus more tire fills.
Most all auto racing sanctions are using it now also, as well as the military for high flying aircraft (it won't freeze). I've been using it in all my vehicles for 2 years now, no problems!
If you do choose CO2, I wouldn't use a liquid tank (syphon, dip tube) as you'll be dumping the CO2 into the tire in liquid form and have it return to a gas form 'in the tire', probably not too good for the tire. Just a thought!
I think you should do some more background on the physical properties of gasses and chemicals. How is CO2 "wet?" (it's not!)
Larger molecules? No! N2 molecular weight = 28.014
CO2 molecular weight = 44.009... I will agree that this is not the important part, but the size of the molecule is. Still, N2 is actually smaller than CO2.
Both molecules are linear, so the length is not as important as the diameter of the largest atom.
Atomic radius of N = 65 pm
Atomic radius of O = 60 pm
Atomic radius of C = 70 pm (pm = picometers)
Major radius of N-N (N2) = 65 pm!
Major radius of O=C=O (CO2) = 70 pm!
It will not change pressure when hot? This is very incorrect, gaseous N2 will behave just like every other gas, there is nothing magical about it. You take N2, the purest and driest N2 your can get your hands on, put it in a fixed volume container (how about a tire?) and heat it up, the pressure will increase… guaranteed.