progress report, and question

The primary is finished, and turned out to become 16 turns of 5/16"
coppertube, spaced 5/16" _flat_ spiral. It is supported by what looks
like a wheel off a waggon from the western aera: a octagon frame of 2"
by 2" beech just big enough to surround the secondary`s 6 inches, with 8
tapered spokes. At the perimeter these spokes are attached to an
interrupted ring of 1" coppertube to form the strike rail, and the coil
itself is nestled in acryllic combs which are glued in routed radial
grooves in the spokes. The hub is elevated from the base by 4 pcs. 3/4"
by 1 1/2" and 10" long posts. These posts also guide a 7" by 7" platform
that can be raised, or lowered, as supported by dowel pins inserted in
holes drilled in 2 opposite posts. The platform has a round 1/4" deep 6"
diametre cavity routed into it, to accept the bottom of the secondary,
which is also guided by a acryllic ring recessed into the top of the
hub. This way, I can raise, or lower the secondary, should coupling
btwn. pri. and sec. become troublesome. 
Now that I have produced something, I will allow myself to ask more
I asked around for neons, and would have to buy a new one at 125$ for a
8000V 50mA unit. Since I have the impression that neons are whimpy and
fragile transformers, and I could get a 3kW core for the same money, + a
bit, I bought just that. It is a BLUM modular core, which means it is 4
separate sticks of transformer laminations. These laminations  are glued
together, and ground to a fine finish where they mate, to form a U-I
style core. The section is 2" by 2", and the winding window is 6" by 2
3/8". Voltage per winding: 0.88V.
I will wind a transformer, 15000V, 0.2 A on this core, and now the
I wouldn`t attempt to start the coil up, without a variac, so I`l buy a
16 A variac, (any European members got one?) but are there other ways
that I should controll this beast. I have read about ballasting, but am
not quite clear about, what it means.
In the readme file of rotjit, the author mentiones that it is
necessacary to use an inductor upstream, and I could wind a choke if
needed be, but which walue should it have, then?

Cheers, finn

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