Need advice in Audio Research Classic C-60Amp

I just purchased a classic C-60 to pair with my old Vandersteen 2CE’s.

Right now I’m just using Blue Jeans biamped speaker cable terminated in spades on the amp end. The classic only excepts wire that are screwed in on the back of the app. This means I’m going to have to cut the ends off the spades, and because it is Bi-amped I’ll then have two positives wires and two negatives  going to one channel. 

So my options are to just not use one of each color (one red one black) or twist the two reds together and twist to blacks together.  My question is what is the best way to attach the wire to the amp. Do I need to buy a different type of termination or is it just the bare wire that gets screwed in. And how do you think I should go about doing this with the wire I have. 

Also one follow-up question, if I just cut one black wire and one red wire from the spade, and tape them up, is there anything I should be worried about, sonically?