I carry a framepump now, but I used to carry a mini-pump mounted to the frame and two 12 oz cartridges in my bag.

I used the mini-pump to get the tire up to about 30 psi to make sure the tire was seated and alined. Then the CO2 cartridge to get up to pressure.

I learned a trick in filling a road tire with CO2 that I haven't heard from others. You will notice that the cartridge gets freezing cold as the CO2 comes out of it. If you wait a few minutes for it to warm back up to ambient temprature, significantly more CO2 will come out if you use it again. I do it on the same tire to get it all the way up to pressure.