Generally, i recommend removing one pair of binding posts, then using a small jumper wire from the tube connector to the old binding posts. So you can easily switch back/forth and have the ability to use spades or bare wire if you ever sell the speakers or need to use a different cable/connector.
Here's what I did for a B&W 602 S2 for a customer.

The set that needs to be drilled out you can use a 7/16 inch (or 11mm) drill bit. I ran the but in reverse to friction melt the plastic for a cleaner hole. Then glued it into place with super glue, and in this case, 3D printed some barrels to give them a little more support than just glue.