Viggen, My comment to you about not bi-wiring is better comes from earlier posts by others. Unless you tried a double run of the cable you are using for a single, against the jumpers, I am not surprised you may find the jumpers better. Probably in all cases, the stock jumper should be trashed in favor of what you are doing.
A cheaper (or different) bi-wire cable will not always perform as well as a better single cable, for the reason the single cable is just better, not because of bi-wiring.
I guess you would need a double run or a bi-wire version of the same cables to do a good comparison. B&W actually recommends bi-wiring with their speakers.