Bananas rule, spades drool. End of discussion.

OP:

IMHO, rhodium should never be considered.  It's just too hard to grip well and doesn't conduct very well.  Gold had the least oxidation, but I love me the silver plated one's. :)

Pure copper is a great choice, but will require regular maintenance.

OK, Rhodium is off the list. 

Presumably the copper needs a periodic Deoxit wipe. I have done that before when using bare wire to degunkify.  

Looks like it's "Hi-yo, Silver, away"! 

TL-DR - But low mass BFA style bananas are my favorite. Logically, they just make sense. They have a high rate of contact, they are sprung, so they put a constant outward force on the inside of the binding post, and they are inexpensive. In fact, they fit tightly enough and maintain enough outward force that you wouldn't even need to tighten the binding post and they would be just fine. But tightening the binding post will just further insure they do not get loose and fall out.

My first encounter with BFA style banana plugs were the Nordost Z-plug. I later learned that they were just low mass BFA style banana plugs and are actually very inexpensive to implement. I've since built many different speaker cables using inexpensive BFA style bananas and my current "no frills" Audioquest cables were built by Audio Advisor using BFA style bananas.

My opinion - They are the best value in speaker connections. Maybe even better than bare wire as they do provide additional mechanical grip due to being sprung. They put constant outward pressure on the inside of the binding post hole. No need to worry about how much torque you've put on the binding post nut.

TL;DR, but this (loosening spades) speaks to a much larger problem - the audiophile's fascination with garden hoses for speaker cables.

... Thom @ Galibier

……got the time to check on the spades …..rock solid on my Verity’s which use Furutech and rock  solid on my Accuphase amp. So my spades rule …..