I found the answer on Toomey tech docs
http://www.toomey.com/html/pro-ban.htm
Route the cable up through the frame just like the stock one was. In case the stock cable was routed poorly, the criteria is to keep as big a radius as possible everywhere in the cable, to avoid kinks or sharp turns and to insure the cable is fully relaxed when you turn the handlebars from lock to lock, so that nothing will pull or squish the cable. Attach the cable to the thumb throttle in the same manner as the stock one. Screw the throttle cable into the upper housing fully.
"Blip" (twist) the throttle a couple of times to insure everything works properly, and although everything might not be adjusted properly yet, there is no binding or unusual feel. Confirm the throttle slides bottom out fully on the floor of the carb bore too. There should be approx.. 1/4" of play in the handle end of the throttle cable too, when the throttle slides are fully down. You can now replace the gas tank and seat.
With the air cleaner off the bike you can stick your fingers in the back of the carb and actually feel the slides move. What you hope to accomplish here is to feel which slide moves first, and adjust the other to match it so that they move exactly at the same time.
Using the carb cap cable adjuster on the slide that moves first, adjust the cable play so there is about an eighth of an inch of freeplay between the cable sheath being all the way down in the adjuster and where it is when it starts pulling the slide. Tighten down the lock nut on the cable adjuster and slide the rubber boot down over the adjuster. This one's done. Going to the other side, adjust the carb cap cable adjuster such that when the first carbs' slide just starts to move, this one moves too. Adjust them so they open together. Again, lock the adjuster with the lock nut and slide the boot down to cover the adjuster.