Glad you are now informed and have more confidence. When it happened to me, I "knew" for sure I was going down. As I was twiddling with the brakes, I was moving over to the side of the road with the intent of side-swiping the road cut. Figured that would be better than sliding along the asphalt at 30+ mph. Before I crossed the white line into the road cut, I was able to slow down enough to stop the wobble.
Of course, I stopped completely and inspected the bike. All the usual suspects; flat tire, loose headset, loose quick-release, loose handlebars, etc. Nothing seemed wrong, so I continued down the hill ... at a snails pace. Once off the hill, no hint of the wobble.
Next time out, I was on the lookout for it. I think it might have started happening again, but the inside knee to the top tube seems to have stopped it, if it indeed was starting. I'm just a wimp now on descents ... at least until I regain full confidence in my bike handling abilities. Good luck. I wouldn't wish this on my worst enemy.