Thank you, Prime and Muadeeb,
That is something I haven't checked since purchased new in 2013. When it works, the air blows quite cold but in your posts, I am sure that a low pressure could still be a problem. I actually HAVE the set of hi/low gauges so will try to use them next weekend.
By the way, the clutch seems to be engaging okay and there is not any strange sounds coming from that area when the A/C is functioning. I'll get my assistant (lovely bride) to help me determine if the clutch is kicking out when the light goes out at high fan speed.
Next question: what should the pressure read when in normal operation?