OK that is amazing advice, thank you.

The way I've got it hooked up now, it "seems" to be working, but I certainly don't want to shorten the life of the board!

On page 44 of this service manual is the schematic of the TV's audio amp section. There's a bunch of common ground pins starting with PGND on that schematic. They might just go to the main ground plane of the PCB, not sure. The schematic has them just tying to the ground symbol, does that mean the board's common ground, or does that mean a special amplifier ground for that section of the board?

If it's just the PCB's common ground plane, it should be easy to tie to a lot of available spots (visible in the picture of the board), but if those PGNDs are something different, it will be a little trickier and I'll have to be more careful.

So if that's true, then what you're saying is, my connections to that voltage divider board should be: R+ to R+, L+ to L+, as before, but then, TV PCB common ground goes to both R- and L- of the voltage divider instead of R- and L- of the TV?