I suppose the easiest way to wrap your head around this is to just understand the workings of a centrifugal clutch. A few key points are:
1) As rpm increases, so does the level of engagement. Example: idle is completely free (disengaged), full speed is completely locked (zero slip).
2) Point one implies the clutch works somewhat, but very differently, like a slipper. It slips just enough at low speed to allow the engine to get the car moving without dying.
3) Point two brings up the adjustability of a clutch. Using a clutch with a low rpm engagement point will have a very soft feel. A high rpm engagement will have a very punchy feel, as if the engine has a lot of torque. This is because power increases greatly as rpm increases. For example in a full size car: Just get the car rolling and punch the throttle, versus redlining it and popping the clutch.
With that said to answer your questions:
1) If your clutch is too tight the engine will have to build too many rpm's to engage it. In this case you may wind up with low speed throttle response that is too snappy or in an extreme case, the clutch will never fully lock. That results in burning up the shoes, the clutch bell, and the bearings. Also overall performance suffers greatly.
2) How fast you rev the engine doesn't matter. If the track you run on has great traction, punch the throttle and go.
3) Now that you've read the above, obviously more throttle equals more rpm. More rpm means a higher level of engagement and power output.