Are you opening up your idle valve with the A/C on? i.e. do you have an RPM added to nominal idle RPM? Ideally you'd have enough extra idle speed that the extra load from the A/C is accoutned for by the idle valve during takeoff. Normally (at least in my logs), the idle valve doesn't close instantly, but rather over time after exceeding the minimum TPS threshold.
The answer to most of your questions is yes, Yes I am using CL idle control PLUS an extra air solenoid so that the idle control valve doesn't have to really move when the AC kicks on. I came up with this method over several years and different revs of MS units, finding that the stock ICV just could not give enough air to handle the AC without help. I am not adding RPMs to my target idle speed, tried that and had too much trouble with AC turn off recovery BUT I am adding about 3.5 % to idle duty which puts the idle rpms about 75 rpms above target when AC kicks on. And yes the idle valve does stay open during takeoff.
The thing is that with this small high reving engine, it just doesn't have enough grunt if the idle dips below about 800rpms SO that is why I was thinking that either a cutout based on % of TPS change or a low rpm cutout would allow the engine to recover during these rare transits. Understanding this doesn't happen everytime I takeoff with the AC on, but when you are stuck in traffic sometimes or when I just mess up and give it too much clutch. Just rather have something that was "Automatic" to help.
More thinking on it makes me think the low RPM cutout would be the best way go, that way it would only come into play when taking off from a standstill.