Speakon cables are easy to make. You need some 12 gauge speaker wire and a small screw driver. Twist the back cover to remove it, slide it onto the cable, strip about a 1/4" of insulation from the wire, twist the strands together, push them into the small hole +1 (positive) -1 (negative) and tighten the screw, put the plastic retainer around the cable between the main part of connector and the back cover then twist the back cover onto the front head. Note: the black retainer will squeeze down on the cable to secure it in place.
That is it in a nut shell. Note: you only need two wires for normal cabs and 4 wires if biamping like used on a GK700 RBII amp and cab where the +1 and -1 feed the woofer and the +2 and -2 feed the tweeter horn. Some GK cabs are wired in this manner. Others may not be and would just use the +1 and -1 for both the woofer and tweeter.
http://www.crownaudio.com/pdf/amps/126986.pdf