Yes, the span betweem "idle control" and "full throttle enrichment" is broad -- and those two events (idle and wot enrichment) are somewhat unrelated.

The best way to check the throttle switches is with an ohmmeter. You should see the contact resistance go from infinite to zero ohms (or vise versa) when the the switces hit idle or wide open positions.

Sometimes the "click" is very subtle and hard to hear. Also, I've seen a throttle switch "click" but not change electrically.... so a "click" isn't always a measure of electrical goodness, and I don't think a missing "click" is necessarily a measure of badness...

"...any thoughts on how to check for a plugged cat, without removing it?"

I've read that there are ways to detect a plugging cat using a combination of exhaust manifold pressure and engine vacuum measurements. But I'll be damned if I know the procedure. Perhaps another brickhead knows..
--
Don Foster (near Cape Cod, MA)