Secondary coil

Well as I said before I was hoping to get some results out of my 400 turn 
secondary before I upgraded.....looks like it's not going to happen. The 
secondary coil was the first thing I built on my TC so naturally it was built 
when I knew the least about what I was doing.....this resulted in a 400 turn 
bell wire wrapped coil. What I didn't mention was that the form I built it on 
is wood....wood sagely coated with non-conductive paint but still wood none 
the less.....another thing I failed to mention; I stripped the wire before 
winding it. Basically I built a very nice looking copper pipe *groan* Well 
back to the drawing board, since I'm doing the secondary over again I'll take 
all the suggestions for building a nice one I can get. First off I was 
planning on using pvc pipe as a form this time, I've heard about high rf loss 
from pvc forms, how much effect will this have on spark length? And while 
we're on the subject of rf loss what exactly is it? Can someone tell me 
exactly what rf loss is (and I'm talking about a good description here not 
just a short message telling me what the letters stand for) and why it's bad? 
Then too I've read that thick walls of the tubing used as a form is 
bad....how much effect does this have on a coil and what is the best 
thickness to get? I was also wondering how much there is to gain by building 
a larger coil, instead of sticking with my 4" diameter coil I could go with 
6" or even 8" what is there to be gained from a larger secondary and how 
large can I go before it's overkill? To help answer that last question here 
are the current specs of my TC

Trans: 10Kv .023A OBIT 
Cap: in the process of looking for one with a .0061uF rating (I'll probably 
go with MMC's here)
Spark Gap: RQ's air blast gap
Primary: reconstructing it but I plan to make it 20 turns of 1/4" 
refrigeration tubing angled at 30 degrees
Secondary: that's what I'm trying to figure out
Toroid: plan on getting a 4" x 9" aluminum toroid (made out of dryer hose)

Wow...now that I look at it all I really have is a transformer and a spark 
gap....I"ve had all the parts for my TC three or four different times now but 
ended up junking them for some reason or another....maybe now that I know 
what I'm doing I'll get a working product *lol* Luckily my junked parts won't 
go to waste, I'll get a great looking Jacob's Ladder when I wire all my 
unused caps in with a transformer...

Left, left I hadda good brain but it left...
(p.s. I'll be leaving tomorrow morning to go on a trip and I won't be back 
for two weeks so it may be a while before I get around to answering any posts)