Skinny TC problems?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Black Moon" <black_moons-at-hotmail-dot-com> 

Hi, I have abit of a problem with my tesla coil.. first some stats.
Secondary: 28 awg, 850~ turns or so, 11" winding height, 1 1/4" PVC pipe 
(0.875" from center). 12" major diamiter toroid, about 2" minor
1.5" from center primary about 8 turns, 0.01uf primary cap (Not dead set on 
using this value of primary cap or primary)
Problem being this coil runs at the rather insane freqency of 580khz 
according to the tesla coil calculator. allready have the secondary 
constructed (DOH, should of calced first then built :( )
Iv only been able to get about 2 and 1/2" arcs no matter how much I try and 
tune it, and changeing turns seems to have next to 0 effect on the output.
So, questions are:

Should I keep trying to tune it?
If so, with such a high freqency, should I try lowering the primary cap and 
using a flat primary, or is a cylinder primary ok at 1.5"?
Or try and lower secondary freqency?
if I need to lower freqency, is my only option a large toroid?
or is there another decent way?
Like puting a grounded metal mesh wall 2' around the coil?
Finaly, if I was going to make another coil about 12" tall winding height, 
with 28 guage wire, (aprox 900 turns) what size PVC pipe should I get? 3" ? 2"?