With my parts whats best design

Hi All,

Would appreciate comments on the best design using the parts that I have now.

15kv/30ma NST
28 awg secondary wire (I have a bunch)
lot of 3/16 copper tubing for the primary.

What would be the recommended secondary diameter and turns
primary size and turns
cap size  ( PF ) (plan to make from "visqueen" and aluminum foil

Appreciate all responses