Well, if I turn down the A.G.C delay about halfway and turn up the brightness, the picture has much better contrast. Now when it's set like that, turning the contrast up and down still doesn't improve it much. It's just as if the brightness and contrast control are performing the same adjustment. But yes, setting the A.G.C lower improves the picture quite a bit, granted it's still not as defined as what I see on some televisions of this vintage. I think I'll post a video on YouTube and link it here to demonstrate what it's doing:
http://www.youtube.com/watch?v=b2xBml-w8CI
The set now has NOS tubes in the IF section ( 3 6CB6's ), a new sound limiter tube ( 6AU6 ), and a video amp tube ( 12BY7), all of which were probably unnecessary but at least I know I don't have a weak tube. I haven't touched the sound discriminator ( 6BN6 ) which has a 2 x .01 ceramic cap in use that I might could replace. I have a couple .01 film caps that I bought just in case. It's just a hard spot to reach being that the tube socket is so close to the shaft of the channel selector. But, leadlike had told me that these caps can go open so that may very well be the case. One side of that does go to my buzz control.