Single-wire spades from amp to biwire spkr posts?

Thank you for that. I will do some more research.
From the photos I looked at on some major cable websites,
I only saw biwired cables with 4-wires on each end of each cable. I didn't see an internal biwire option,
or any distinction between bi-amping and bi-wiring.

I just hate stacking spaded-connections on one post.
When I did that once for jumpers, they would occasionally
detach themselves.

It's also possible to have externally bi-wired cables, two lengths of cable going to each speaker, with the two cables joined at one end so that you have only one set of spade terminals at the amp. I've owned Dh Labs and Silverline cables configured that way.

Thanks for that Sfar. I may look into that with my Cardas GR.

If you like your Cardas cables, before buying anything else, you should try a high quality (like Cardas) set of jumpers on the speakers. Run the speaker cables to the MF/HF posts on your speakers, and then jump to the LF posts(or try it both ways and do what sounds best). Instead of stacking the spades, you might try finding jumpers with spades on one end and bananas on the other. That way you can attach the bananas to the posts with the main (spade terminated) speaker wires. If your jumpers have spades on both ends, try some Cardas bananas connected to the spade on one end of the jumpers and plugged into the post with the spade termination. BTW, if you decide to purchase something, there are many internally (and externally) bi-wired cables that terminate with a single set of spades at the amp end (as others have said above). Do a search under cables - speaker, here on Audiogon.

Another option would be for you to construct your own jumpers. It is easy to make a set of jumpers that should perform just fine, and since the length is generally a foot or less, the effect of that wire IMO is about nil, assuming the wire you use is of sufficient gauge (12-14 awg should be fine for the short run) and at least as good as the internal hook-up wire inside the speaker. You can order single crystal copper hook-up wire from Partsconnexion, VH Audio or others, or even actual speaker cable by the foot, and make up your own high quality set of jumpers using spades at one end and bananas at the other. If you are not comfortable with soldering, there are several really good spade and banana models that have compression terminations using set screws. I have Furutech spades with compression terminations, and I believe the highly rated Bocchino Audio connectors also use that method of termination (see the CRL website). If you are using copper wire, some cover the connection using Q-dope, silicon, or other compounds to resist exposure to air and potential corrosion. Many would think using high quality heat shrink over the connected part of the spade should be fine. You will need 4 spades, 4 bananas, 4 feet of wire or cable, and some heat shrink.