I use a single probe Computech. Digital readout with a memory of highest and lowest temps. I just read cylinder #1 and the plugs tell me the rest. They make 2 probe ones also. 5&6 tend to be the leanest cylidners in my motors, but manifold design could be why. Best $300 I ever spent.
http://www.***boat.com/image_center/...putech-med.JPG