CO2 Cartridges!

So I went to my local REI looking for CO2 cartridges.  They had 16 gram and 20 gram options.  I normally get the 16 gram and I know they have plenty of "oomph" for my road bike but for some reason I want to buy the 20 gram cartridge (they were out).  I'm wondering if they would have enough air to "plump" the tire before I wrap it around the wheel, something I normally do with my mouth on the side of the road.  Here's 1 vote to standardize on 20 gram cartridges for road bikes, they're not just for 29er's anymore!