Without a doubt, that wasn't the easiest spot to clean up. I managed to get most of the dust and black smut out of there, though.
I went ahead and coated a little more of the flyback up along the backside and towards the top of it. This flyback must have sat under layers of dust for years before I bought this set, and even though I had done a "cleaning" in that area before, I was very gentle about it. It didn't help any that this was all right in the path of the falling chunks of plastic from the yoke cover. Someone had suggested that I coat the flyback with something before, but I was caught up in chase of hunting down all the other problems that I never got around to it until now. I'm glad I did. Cleaning this up and coating the flyback seems to have really helped, and I'm not hearing or seeing any signs of a leak anywhere now.
After hooking up my coaxial cable, I was able to see that my horizontal was way off but after running the set for a few minutes and adjusting a few things, I got it to hold on most of the channels although it's back to losing sync when I change channels. It would stay that way for awhile at first, but now it's more of a 2 or 3 second delay.
I can't say that my contrast has improved, so I'm thinking I should try substituting that 4uF capacitor with another with the possibility that it may be leaking. As I said before, I think I might have gotten it too hot when I installed it.