I too am very familiar with both "the two little words that keep a marriage together", ("Yes Dear,") and "the three little words that keep a marriage together", ("I was wrong".)
As for negotiation, I've heard that "The difference between a wife and a fanatical terrorist is that you can negotiate with the terrorist!"
I'm not familiar with the Atlas HO-6 kit you have. Terminal joiners however are simply an easy, no soldering, way of connecting feeder wires to the track. Obviously one wire from each pair goes to each of the two rails, but I think you already knew all that, and are asking where, specifically, on the HO-6 plan, the two sets of feeders are supposed to go. I don't know, and without seeing the track plan for HO-6 I can only guess. If that track plan includes an oval loop of track, the two pairs of terminal joiners may well be intended to go one pair on either side of the oval. Hopefully, one of the other members will be familiar enough with the Atlas HO-6 set to help you. I'm surprised Atlas didn't show the recommended location for those terminal joiners on a diagram shipped in their kit.
Good Luck, Have Fun;
Traction Fan :smilie_daumenpos: