if you go to countrycurtains.com you can see their rod sizes and the rings they've paired with them. i like their rings, they have silicon linings and slide quieter than the ones from pottery barn.

standard purchased panels have 7 rings per 50" panel.

When looking for drapery rings to fit your pole make sure they are giving you the interior dimension. That way you know if it will fit on the rod. If the sizes you mentioned earlier are the interior dimension then I would go with the larger ring size. It looks better if the rings have a little "breathing" room.

Most 1 width panels are 20" wide when pleated due to the 2.5x fullness. Cartridge pleat is usually more like 3x fullness because of how it is sewn. This usually needs 7 rings per panel.

Remember the outer most pin hooks are suppose to be returned back to the wall and not be connected to a ring. I can share a photo if you would like to see it.

Yes. Actually that was why it is done. One ring goes on the outside of the bracket (between the bracket and finial) and then the last pin hook returns to the wall. These two things together ensure the drapery stays in place when it is opened and closed. The return back to the wall also helps block out as much light as possible from coming inside.

The return on custom drapery is still done even with stationary panels because of tradition.

Thanks!