Hello BFrank,
While the wire nuts are cheap and effective, they look a bit unprofessional or unfinished. The Neutrik Speakon connectors (NL4FX female and NL4MMX male) would be what I would try. They run about $6 each and have set-screw or solder wire connections. Neutrik claims the contacts are rated for 50 amps! You can find more info on them at parts express-dot-com.
While the wire nuts are cheap and effective, they look a bit unprofessional or unfinished. The Neutrik Speakon connectors (NL4FX female and NL4MMX male) would be what I would try. They run about $6 each and have set-screw or solder wire connections. Neutrik claims the contacts are rated for 50 amps! You can find more info on them at parts express-dot-com.