Vintage Speaker Choice

On my vintage but completely different system, the choice of speaker wires didn’t make a significant difference unless I run very long >15’ runs. Any decent 12awg stranded copper cable should work. Are you connecting them up in parallel?

For all but my main system I still use 14 gauge stranded wire, and have never heard a difference switching in much more expensive cables.

Zar - glad to hear about your stacked pair.  Should give you lots of pleasure .... image much better than single speakers alone, plus solid frequency response top-to-bottom.