I did this for my Kadrons. You just need to modify the left carb. Don't tap the manifolds as the the vacuum signal is completely wrong. It's pretty straightforward to do but you need to remove a plug from the carb body and block up a tiny hole just inside the carb throat by the throttle flap (use a tiny bit of liquid metal or JB weld).
The hole you need to tap is on the right side of the carb as you look into the engine bay (will try to get a photo for you) and has a thick brass plug in it. The way to remove it is to drill a small hole into (not through!) it and then screw the tip of a PLASTERBOARD SCREW into it. It's essential to use one of these screws as it has a long, sharp thin point that will grip the brass stud. You can then gently lever it out with a claw hammer.
The hole you need to block is the lower of the two (circa) 1.5mm holes that sit either side of the throttle flap when it is in the closed position. Both holes are connected but if you don't block the lower one you will draw a massive vacuum which will advance your dizzy fully at idle. Poke a short section of wire into the hole and seal it in place with some JB Weld. Make sure the JB is in the hole and not just smeared across it as you need to sand it flat.
I have a length of the correct diameter tube for the takeoff if you need some (bought about a foot but needed an inch!) which is a snug fit and just needs to be tapped into place (add JB Weld for belt and braces). I'm happy to post you a bit if you PM me your address.
