Remember that you can have the best of both worlds. All you have to do is cut the armored cable between the switch and the coil. Then you can have the oem switch in the dash and the original coil on the firewall albeit without the hassle of some day being stranded.It takes awhile [I've been there], but it can be done and if in fact they are different lengths then it becomes a simple matter of cutting a regular wire to the length you want. As I remember I first cut the cable housing in half, then proceeded to trim the armoured cable at both ends therby eliminating it. I think I had to use two hacksaw blades. That should solve your problem.

Have a happy hacksaw day. Jim