3-1000z coil, more questions

["Ross Overstreet" <ross-o-at-mindspring-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I'm still working on the 3-1000z tube coil.  I have updated the schematic to
include most of the suggestions you guys provided.  The schematic is still
missing some RF chokes, but I'll draw them in as soon as I figure out how to
make them.  As you can see from my tube page
http://users.better-dot-org/roverstreet/projects/tube_coil/tube.htm, I have the
platform complete and have started bolting things down.  Guess I'll jump
right into the questions.

1.  My secondary is 4" x 23 5/8", wound with 0.021" magnet wire, and has a
measured resonant freq of 400 KHz.  (This is surprising b/c Medhurst &
Wheeler predict it to be 375 kHz)  I have a handful of 2500pF, 30KV doorknob
caps that I planned to use in the tank circuit.  I plan to use 12ga THHN
wire (.135 OD) wound on a 6.25" PVC pipe for the primary.  When I started
running the numbers, looks like I can get near 400kHz using one of the
2500pF doorknobs and around 18 turns in the primary.  Are these reasonable
numbers?  Should I aim for less primary turns and more C?  More L and less
C?

2.  I don't really understand what the grid-leak network is all about.  I
have a good understanding of disruptive coils but this triode stuff is
making me feel dumb.  It would really help me out if someone could give me a
general overview of what is happening in the typical triode TC circuit.

3.  Anyone see anything terribly wrong with the schematic (other than wrong
values in the tank circuit and lack of chokes)?

4.  I know that the leads from the filament transformer to the tube should
be short.  Is 2.5ft with 10ga wire too long?  I can mount it under the top
deck right near the tube if I need to.

If I ever figure this !-at-#$ thing out I'll be sure to thoroughly document it
on my page so others can come up to speed more quickly.

Thanks,
Ross-O