Reducing O2 when racking w/ grade school science

I always rack my beers using a racking cane and some tubing running to the bottom of a new carboy, but I've got some sours I'd like to rack soon and I've been thinking about how I can keep the oxygen as low as possible when transferring.

Does anyone remember the grade school science trick where Mr. Wizard takes a pitcher full of CO2 and pours it on an open flame to extinguish it? My thought was to mix up some CO2 in a pitcher using vinegar and baking soda and perhaps using a funnel to pour it into my destination carboy. The idea would be to get that blanket of CO2 sitting on the bottom so that when I did start to transfer it over it would start in a low oxygen environment.

Has anyone else on here tried that, or seen any difference with it?

I have purged carboys with a co2 hose. I am sure there are benefits, but I didn't see any. Having the hose dangling in there seemed to give another opportunity for contamination. I do purge corny kegs for a few minutes using the gas inlet. I let the co2 settle for about an hour before racking, yet I still avoid splashing.