Big top loads

["Alan Sharp" <AlanSharp-at-compuserve-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Greetings all,

I'm looking at building a much larger topload for
my coil, and I was considering moving away from
to toriod to a disc shape (a filled in toroid if you like)

 ()----()   becomes  (PLATES)

So I will still have the outer curviture to hold back
the breakout.

Am I right in thinking:
firstly that the capacitance of this disc will be almost
the same as for a toriod of the same dimensions?

secondly the disc will electrostatically shield the 
the secondary exactly as a toriod would?

Alan Sharp (UK)