what connectors do you use on your jumpers?

just wire. would never use bananas. i also like pro binding posts and neutrik locking connector. otherwise just wire is enough. i clean it from time to time to prevent oxidation.

spade on one end and banana on the other makes for a universal hook up whether you have bananas or spades on your speaker cables.

If you can remove the terminal nut completely, ring connectors would be more secure.

It should be fine using 2 spades at 1 connector. Personally I like bananas better because you get more of a surface area connection. Also with spades you check them to make sure they don't loosen up. I used the wbt locking banana and didn't feel there as much of surface area connection but I could be wrong. The weight of the cable might justify a locking banana. I have Nordost now witch is a light weight cable compared with Jps S3 that had the locking wbt's.