Ray, would you care to share what Al told you? And what engine / carb are you asking about?
The problem with your question is that it seems to be asking one question, half of which relates more to 1 style carb and the other half relating more to a different style carb.
Al has extensive knowledge of the Walbro, Tilly, etc carbs where you have needles that you can use to tune while you are driving. In this case, you can definitely use the EGT to help tune the low speed needle “on the fly”.
When it comes to tuning an idle jet in a Dellorto or similar carb with jets that can be changed, like a Dellorto, John Savage has a lot of knowledge, and I’d agree with him. Find a smooth idle (EGT not very important here), and focus mostly on needle/clip/atomizer and mainjet, and adjust to changes in air density.