Was browsing around on BDK Race Engineering's website for some Kawasaki AR stuff for one of my other bikes, and stumbled across these 2/3/4 pull throttles. These are apparently intended for large cc multi cylinder 2 stroke racing beasts, like the Suzuki TR750 or RGB500, but would probably work great for a dual or triple carb moped.
Unfortunately these specific ones are wildly expensive haha but maybe there are cheaper multi pull throttles out there. This may be a good route instead of splitting a cable.