You would expect the plugs to be darker in colour from idle than say, doing a plug chop from WOT. I wonder if you are worrying unnecessarily? A picture of the plugs would help.
Try adjusting idle with the adjustment screw on top of the carbs - right hand side under the tank. Do this when at normal operating temp, and it may lift your idle above where it would normally stall at the stop sign. All adjustments need to be checked at normal operating temp by the way.
You can remove the IMS screws with the carbs on the bike, however those washers and o rings are small and can get lost easilly. I usually place a light-coloured towel under the carbs if I do this, to catch any errant parts. Sometimes, the washer or o ring or both can get stuck in the body when the screw is removed, so you need to watch for this too. If I were you, I'd try out the adjustments first if this is new to you.
Others will hopefully chime in here, but I think it is unusual for these PD carbs to be rich at idle at the stock setting. Is your air filter original Honda? I know some have had problems with tuning depending on the filter used. Do you know if the slow jets are stock? And remember it's an old motorbike - sometimes you have to make compromises for their quirkiness and you shouldn't expect performance like a brand new widow-maker. Also, with reference to your other thread, you need to rectify your exhaust leak before doing any tune-ups.
