Need help with speaker wire connection to ARC Classic 60


So I have this ARC Classic 60 with the screw down speaker cable connectors at the back of the amp.  The screws are flanked by fins that prevent standard spades, and of course bananas are not an option.

What is the preferred connection here?
last_lemming
Why would you put those on barrier strip connectors, just to use banana jacks? Did you ever look at a banana jack closely? They make several small point contacts inside of the hole, surrounded by open space so that things can slowly oxidize. They were never intended for long term connections, they are for quick and dirty test instrumentation connections and just the process of inserting and removing the banana jack helps clean off the oxidation each time it's set up. They were never intended for set it and forget it applications.
A ring lug on a screw type terminal forms a gas tight seal when tightened and is forever.
There are many 50 or 60 year old industrial controls with hundreds of wires secured by ring lugs and screws. In all my years as a tech, the only failure I have seen is if the screw was never tightened. If it's a high voltage/amperage circuit it fails almost immediately, on low voltage control circuitry it can take years before oxidation takes it's toll and the circuit fails.
I have never seen so much misinformation as in audio. Bling seems to outweigh good engineering all the time. Yet folks will pay thousands of dollars for a piece of gear (superbly engineered and built) and use junk connectors to hook it into their system. Really amazes me.
BillWojo
I had the same issue when I owned an ARC D70Mk2...which was a truly great amp. The solution for me was to have the speaker cable company add small spades at the amp end ( most can do this with no problem).
Do NOT snap off the fins or try and bend them...bad advice above!! 

Why would you put those on barrier strip connectors, just to use banana jacks?
It accept bare tinned wire as well.

https://images-na.ssl-images-amazon.com/images/I/51phA0WYkaL._AC_SL1280_.jpg
There are many 50 or 60 year old industrial controls with hundreds of wires secured by ring lugs and screws. In all my years as a tech, the only failure I have seen is if the screw was never tightened. If it’s a high voltage/amperage circuit it fails almost immediately, on low voltage control circuitry it can take years before oxidation takes it’s toll and the circuit fails.
I have never seen so much misinformation as in audio. Bling seems to outweigh good engineering all the time. Yet folks will pay thousands of dollars for a piece of gear (superbly engineered and built) and use junk connectors to hook it into their system. Really amazes me.

@BillWojo, calm down my friend, I were a tech working at Toshiba Singapore 40 years ago.
I’ve been using what inhifiman suggested with banana plugs in my old McIntosh amplifier for several years with no issues. I do remove them every now and then and clean them with alcohol just to keep the contacts clean. They work very well.