RF chokes

First, I would like to thank you for your help, I now Know how I will build
my first TC, and that's because of your help...

I still have a few questions, though...

1) As Dr. Resonance's plan tells to do, I plan to put RF chokes between the
security gap and spark gap. But instead of building them, I will ask my dad
to get me some, for he is in the electronic business. But before asking him
for some, I need to know what kind of chokes (impedance etc...) I need for a
12KV 30 ma NST...

2) for such a small TC (it's my first one...) do I need to build a RF ground
or can I use the house's???

Thank you for your help...