new secondary

I introduced myself a while back and now it's time to fess up. I've been
playing but not reporting on progress. I have got some pictures to put on my
website "real soon now". I'm nearly ready to jag in my 10Kv 28ma OBIT and
try my 12Kv 60ma neon. I've gotten solid discharge sparks up to about 8.5
inches and spay type sparks up to about a foot or so. I don't know if that's
good for an OBIT or not, I'm using salt water caps so far.

I made my first secondary on a 4 inch piece of clear Plexiglas tube and
coated it with spay acrylic varnish. It seems to work OK but I wonder if the
clear acrylic spay was as good as any to use? It looks fine.

My main reason for a message right now is this:

I had some 22 gauge magnet wire left on the spool and decided to wind
another secondary on a piece of 6.25 inch OD PVC drain pipe. I was shooting
for the magic 24 inches but ran out of wire at 22 and one half inches of
coil. Is a 24 incher really preferred or would a 22.5 work just as well. I
want to decide now before I go any further with it. I've got a lathe setup
now so winding takes no time at all.

Any and all suggestions appreciated.