The worst thing to do is to mess with the mixture before you know the CIS is functioning correctly. You just end up masking issues and making the problem worse and more difficult to diagnose. Once you are sure you are free of air leaks (remove the oil tank cap and if your rpm's drop then you know you don't have a significant leak) and your timing is right, WUR, AAR, AAV, deceleration valve, O2 sensor, frequency valve, micro switch, throttle position switch, TTS, OXS relay, dizzy vacuum pod, temp sensor, injectors, spark plugs, ignition wires, fuel distributor, accumulator, throttle body and sensor plate (phew - I'm sure I've left something out) are working correctly and in spec, then you can set the mixture. There's the method above in the video which puts you in the ballpark, then there's the measured ways i.e. the frequency valve duty cycle signal method from the test pin in the engine bay and the factory adjustment using a gas analyzer. The "dummies" thread goes through all of this. It's a really good read.
There are lots of real experts here like boyt911sc (Tony) that love this stuff and are always ready to jump in and help. He helped me immensely.
I spent a lot of time going right through mine and it now works really well and it's very reliable. If the car has not been sitting it fires up right boom right off the key warm or cold. If it's been sitting it needs to crank for a couple of seconds to build the fuel pressure back and it fires. I still have an issue where in warmer weather the AAR tends to close a bit too quickly and I need to give it a bit of throttle to help it warm up (or just drive off) but it's a 40 year old fuel injection system so I feel like it's never going to be like a modern system. One day Santa will bring me a digital ITB setup like Mr. Kosmal's ... one day ...
