Triumph Repair: MK3 unstable idling, mixture settings, vacuum leak

Question
I have a Spitfire MK3, recently replaced the BO needles on both carbs and retuned her.  Spark and ignition timing is perfect, good compression and the carbs are balanced.  She revs instantly when I press the accelerator and drives very well, but I cannot get her to idle constantly.  Where else would I have to check for the problem?

Answer
Look to the idle mixture settings; you usually have to adjust to maximize the rpms, then reset the timing & balance of the carbs; its a repetitive process in order to get it all working together;

Sometimes the problem is a vacuum leak, but since it revs and drives fine, if there is a vacuum leak, it is small.