Just a follow up for those who care,
After adjusting the grid bias down enough for the dots to go away all day, I found the signal to be too weak. I dug into it to fix it properly, and traced it down to an IC, forgot which number it is, but it's a Tl072ACP, an 8 pin dip on the hv board. Thanks for the help, got us back up and running again!
Thanks, Steve Kamego