Just fitted one to my Super Rocket, strange really using one now after all the years without one.
Using threaded cone type from Burlen, good quality and appearance on Mk 1 Concentric and screws straight on.
You will need to go down on main jet and lift the needle up a notch.
Also fitted extended tickler.
After the Carby mods my bikes been a pig to start from cold, but ran quite well, found today tappets tight and float level to high, will road test tomoro after adjustment.