T.C. design


Could someone offer some pointers on Tesla coil design? I am mainly concerned
with two topics: design sequence, and performance enhancing techniques.
The design sequence that I plan on taking is geared towards using the materials
at hand.  The performance enhancing techniques are things to consider when
designing the coil.  That being said, here's what I am planning on doing:

Coil design:
	Given a bunch of 22 ga. magnet wire and a 4" thin wall PVC pipe for
	a form, design a coil that works well.  I plan on figuring out
	if the wire diameter will allow between 400 and 1000 turns and 
	produce a coil with a height to width ratio of about 4:1.
	Then, calculate this length, and figure out the 1/4 wave frequency
	based on this length.  Given the frequency, coil size, and number
	of turns, find the inductance.  Then calculate the capacitance
	that is needed to make the LC secondary circuit oscillate at the 
	desired frequency.  Then, once I have the secondary designed, 
	design the primary coil so that it is about 3x the diameter of the 
	secondary coil.  Figure out the size of the capacitor that I need
	based on the size of the primary coil and my transformer output.

	Now the question:  Does anyone who has successfully designed a tesla
	coil see any problems with this approach?  

	I frequently read that the old coil designs are less efficient than 
	the modern ones.  The question is why?  Is it strictly the materials, 
	or is it some choice bits of knowledge such as "don't make your 
	coil over 4 times taller than it is wide".  I would appreciate it if 
	I could hear about specific design enhancements made to the primary/
	secondary system designs.  I figure that I can get the spark gaps
	figured out later, though that may not be a good idea:  perhaps a 
	coil system is also designed around a specific type of spark gap.

Background info:  I built a working 3" dia. tesla coil from the TCBA news.
It works great, but now I want to go to something slightly bigger that I 
designed by myself.
I can use the design programs, but I would like to know how to do it first.

Any and all comments are appreciated.

before I use a "crutch".