I realized that I could return $255 in parts I bought to repair my car (which incidentally just proved I had a different problem) and spend less than that to completely replace the problematic system with a modern version.
For the gearheads, converting an early 90's igniter/coil/wires setup to coil on plug. $50 for four coils, $10 for four connectors, $8 for ECU wiring pigtails, $70 tach adapter, ~$50 in wire (buying way more than I need because I have other uses for it), and $11 in crimp connectors (I already have wire loom/tape/etc to build the harness). $109 vs $255, and a superior solution anyway!