Need help with speaker wire connection to ARC Classic 60

A) Bend the fins down enough to fit a spade.
B) Bend/trim the spade enough to fit between the fins.
C) Both

I wouldn’t bend trim or modify your Classic 60 or you’ll just hurt it’s value. If you don’t have the skills, no disrespect, have Chris at VH Audio or someone else make you some jumpers so you can use other heavier cables. Cardas, Audio Quest and others make spades that work just fine on your amp. The dividers/fins are plastic I recall so they’re not going to bend easily and again it’s a classic amp and I wouldn’t mess it up.

I have no desire to modify the amp.  I ordered some Kimber Kable 8tc in bi-wire configuration with bananas on the speaker end and bare wire on the amp end so I can terminate once I found the right solution. 
One thought I had was to bend the wire in a hook and solder, but I’m not sure how good of an electrical connection that would provide.

Those fins will most likely just snap off if your not careful. That is called a barrier type terminal strip. Your lucky to have them, AR knows what they are doing. Your best connection is going to be with good quality ring lugs carefully crimped onto your speaker wires. Tighten the screws holding the ring lugs snuggly and never ever worry about your speaker connections at that end of the cable. If your lucky, your speakers support the same type of connectors as well.
Banana type connections are designed for temporary connections in test gear and how they wound up in stereo gear is a mystery to me. They suck! they fall out or can be easily pulled out, sometimes shorting the amplifiers outputs on SS gear costing major dollar repairs.
When using an amp with 5 way binding post I never use banana jacks, either bare tinned wire or a crimp on connector.
Did I say yet that banana plugs suck? Yes, they suck! Get rid of them.

BillWojo

This is what you need:

https://www.amazon.com/Hi-end-Adapter-Speaker-Connector-Wy-yp01/dp/B00X9FET7I/ref=pd_sbs_23_img_0/13...