Here's my observations. I’ve been playing with speaker jumpers the past three weeks. My speaker cables are quite good – Von Gaylord Chinchilla.
Pulling the brass jumpers, I tried three different jumpers. I also tried all the various jumper configurations. Jumpering up from the bass terminals was the best in my system
The three jumpers (all bananas) were: simple Supra Classic 1.6 , Wireworld Platinum Eclipse, and Duelund tinned copper (12 ga-Acoustic BBQ). My observations are the jumper will cause the speaker to sound similar to like the speaker cable used was the jumper only. Or heavily weighted that way. So, in other words, if I put in the Supra jumper, the system sounds much like I used the Supra wire as the speaker cable.
The WW Platinum Eclipse and the Duelund jumpers were clearly better in regards to accuracy and imaging. The Supra tends to bass heavy and lower resolution. The WW probably beats the Duelund by a bit in all regards, but they are pretty close. I haven’t critically listened yet. These are just my quick observations. For the money, the Duelunds are probably a bargain.
This is just what I hear in my system. Based on my observations, I would tend to think jumper as good or better than the base speaker cable should be used.