Since those seat covers are going to the scrap yard. I would suggest splitting the backs and cutting the wires up close to the tops of the seat near the speakers. If Roger's installing speaker seats into his Formula like I did with my 87, he will need extra wiring to splice into his existing wires to give him enough slack to work with the wires.
Same with the radio plugs. Working back inside that little radio hole is difficult and with the way my wires were cut out, I may have to remove the dash and skeleton to be able to solder and heat shrink the connections. Every bit of extra wire is appreciated.