Single-wire spades from amp to biwire spkr posts?

All the major cables provide and internal bi-wire option which is what you're asking for. No problem.

Almost all bi wire cables come the way you speak. If both end had 4 wires, it would be for bi amping in most respects.

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.