Thanks for the advice, Nate. I retested this morning and all 8 tubes passed with no bright, white flashing. Two of them still blinked during the K shorts test, but I won't worry about that now. I told the seller about this and that the tubes were all acceptable.
I also was able to solve another problem today. The fuse blew, probably due to contact cleaner in the volume pot. That was a couple of weeks ago. I removed the fuse and put the holder back into the upright tube that holds the fuse. Without a fuse, I managed to jam holder in the tube. I was finally able to remove it today with the help of WD40 and a paper clip, that I straightened and put a small hook on the bottom. A new fuse is now installed. I'll install the tubes tomorrow and see how everything works.
Edit:
Installed the JJ's and gave it a try. My systems is now playing the beautiful, beautiful music again.