That looks interesting, but the amount of air exposed to the beer during what I did seems extremely small. The headspace is small and full of CO2, and the lid is only off for a few seconds. Then you can blow in more CO2 to reduce the O2 concentration in the keg.
Is there some reason people don't shoot gelatin into fermenters as they do transfers? Seems easier. Pop the airlock off a bucket or open a little screw cap on an All Rounder; shoot gelatin into the hole. Close everything back up.
I'm going to be using buckets for most beers. I don't know what to do about oxygen, if I decide to do anything. I could put a post on a bucket lid and push CO2 in slowly while it drains into the keg, but I would still have an open keg and a length of tubing going through the mouth. I guess it's possible to rig up a disconnect on the keg side and a hose clamp to keep the tube from blowing off the bucket spigot.
I once left a heavy ale in a keg for months and months. It only got better. Back then, I just ran a tube from the bucket to the bottom of the keg, with the lid off both. It makes me wonder how much oxygen has to be in there before it becomes a problem.