Hi,
you can either use a CallType based number (how many calls at a CallType regardless of skill groups) or a SkillGroup based number (how many calls queued at a particular skill group regardless of the CallType).
Which one?
Just a quick note: if there are more scripts or call flows sending calls to a measured point, then the number might not always be accurate, and it may lead to problems. For instance, this may happen: "There are 2 people in the queue. No, there are 5 people. Nope, only 1. Now, it's 10".
G.