Hi Peter,
That was exactly what I did on a recent 74 R90/6 upgrade. The bike didn't have the clutch switch and customer asked if I would add one. I bought the switch from EME, cut the cannon plug off, and added female connectors. I use plain connectors, soldered and crimped with custom cut shrink-tube. For most of my connections I use a product called NO-OX-ID, an electrical contact grease. Dielectric grease does not conduct electricity, however NO-OX-ID does and has anti-corrosion properties, which is excellent for our bikes.
I hope this helps,
Scott B.
Scott Blaylock