I'm going low mass. First on my speaker cables, eventually on my RCA plugs.
GR research sells Electra tube connectors which seem a bit pricey to be so imperfect.
For the speaker cables male it is easy to find the BFA plugs mentioned above. For the Female, all I find is the KLEI harmony and they aren't long enough to attach through the wood panel of the back of a speaker. I'm thinking of making my own out of copper rod. I have a nice machine shop. I'll bore copper rod to the right diameter (about 4.25mm), turn the outside to the thickness I want, press it into a delrin rod and thread it to fit into the back of my speaker. A bit of work but I enjoy it OTOH, if someone knows of an off the shelf low mass female that will work I'll jump on it, my time isn't free.
Jerry