Going further.... Jeffrey, I just looked at the other YouTube video you posted in 2010 at Poley Mountain, Massachusetts. It's also a POV video--helmet cam, I presume--and you cannot see much of your movements at all. I assume that it was shot before the new Daleboots? In any case, I do not see a glaring asymmetry that would justify such a discrepancy in your right and left canting (-3 degrees right, zero left).
I DO see--and it shows in your other video as well--a pronounced "stepping" movement, also known as a "pushoff," that begins your turns. And in both videos, you can see that your upper body also rotates first into each turn, before your skis turn. These movements cause your skis to skid into the turns as the rotation and step twists your outside tail out. It's a common movement pattern, and an error if your intent is to carve your turns smoothly. It can be caused by many things, but one of them is "overedging"--a boot alignment problem that is commonly addressed by canting with the thick side out, as you say was done on your right boot. (Over-edging makes it difficult to release the edge of your downhill/new inside ski as you initiate your turn, but encourages stepping uphill and away from that engaged edge.) Even when the canting issue is corrected, the movement habit will remain until you address it specifically.
Again, this is about 90% speculation, based on your description and on the very limited video that we have. It may be all wrong. But I am still curious about the massive discrepancy in the canting between your two boots. I wonder if there might be other issues at play--leg length discrepancy, for example. I would love to see more video from more advantageous camera angles. And I think it would be money well spent to find a good instructor to assess your skiing live, as well as another visit to your bootfitter.
PS--one quick question: When you say that your skis seem to "diverge," does that happen when you are in a straight run--as on a cat track, or gliding along the flats at the bottom of the mountain? One sign of being underedged (which would be the case if you have too much cant with the thick side out) is skis tending to want to drift wider when you glide on the flats. As your track widens, the skis, which might have been riding their outside edges, become flatter on the snow until they find a place where they can glide flat and straight. If that's what you feel, it further confirms my gut feeling that you have too much negative cant on your right boot, at least....