Paul,
I prefer the 9437 separate black and red screw-type plugs. Don Masso and I used a bunch of them on his layout and they work great - tight, easy to connect wires to, etc.
The 9437 can be back or side wired, and in my opinion provides for a more secure wire clamping action.
If you put the wire in the side hole then use the screw top to clamp the wire, you can piggy-back another banana plug if needed. Or, you can push the wire in the top hole, bend it to go out the side and clamp it that way. Either way works well.
All banana plugs should be the same size (plug diameter) so any banana plug should fit any banana jack. These units have spring metal along the tip to make a tight fit when plugged in.
Ed