Evan,
I use a Napa SL-199 Switch which is a late model GM cruise control switch and a AR-294 relay which is a 80's VW/Audi headlight relay. I use the original solenoid and govenor. I fabricate the carb/linkage bracket and make up factory type a wire loom using the correct color coded wires.
I have several of my OD's currently cruising the freeways in So Cal. If you would like to e-mail me direct I can give you additional info on the hook up. Fred