First Tesla Coil hints?

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: First Tesla Coil hints?
From: Tesla List <tesla-at-stic-dot-net>
Date: Fri, 20 Feb 1998 08:06:36 -0600
Approved: tesla-at-stic-dot-net

----------
From:  Scott Cutler [SMTP:spcutler-at-ucdavis.edu]
Sent:  Thursday, February 19, 1998 8:25 PM
To:  tesla-at-pupman-dot-com
Subject:  First Tesla Coil hints?

Hey guys.  I've been reading this group for several months now, and have
found it quite interesting.  Right now I'm trying to finish my first Tesla
coil project.  Here are some specs:  
4" x 14" secondary, 24 gauge wire
15kv 30 mA NST 
Standard spark gap, 2 1" metal spheres (metal drawer knobs) 
Bottle capacitors (read on)  6 turns 1/4" copper tube conical primary
(about 20 deg. incline, 1" spacing center-to-center) 

I think everything is pretty much in order.  I haven't finished assembling
it yet, so I have some questions first.  First, does anything seem too out
of whack?  I know that it's hard to go TOO wrong on a Tesla coil, as long
as you're not trying to make 30' sparks, but any improvements I should
deinitely make?  I chose a conical primary because I've read that they're
easy to tune and I suppose it's something of a compromise between flat and
straight helical coils.  I think the spark gap is pretty good, the spheres
are nice and round on one side, and hollow on the other, so they should
cool fairly well.  
About the bottle capacitors:  This is my big question. 
Right now I've got 6 "David Lima" style bottle capacitors built. According
to the specs in the instructions and some calculations from a Tesla Coil
computer program, the capacitance is about right for my power supply (4.3
nF, DL claims).  Actually, I think I remember 5 bottles being a little
closer (3.7 nF), but my memory may be off.  My biggest worry, though, is
the voltage limit.  Bottles that are certainly not thicker than 1/4" don't
seem to be able to contain 15 kv, if you go straight from the tables.  Or
does the salt water offset this?  Comments? By the way, I got the
instructions for the caps from this address: 
http://www.eskimo-dot-com/~billb/tesla/cap2.html 
One last thing.  I've noticed some discussion as to the advantages of
running a parallel gap and series cap, or a parallel cap and a series gap.
Any advice, or does it really matter too much on a first coil?  I'm not
going for huge sparks, I just want it to work; I can fiddle with it later
to optimize it.  
Well, that's about it for now.  Any additional observations are more than
welcome. 
Thanks for your time!

Scott Cutler