cap specs

i know this is going to be a broad question, but here it is.  i have lots of
6mil poly, rolls of 14" wide al flashing and a 9kV 90 mA voltage source,
could someone help steer me in the right direction as to dimensions for a
rolled poly cap, considering series combinations?

kevin wahila

p.s.  just a side note, but i have collected several neon transformers and
unpotted them, soaked them in gasoline then let them dry.  i found that the
tupperware containers that are made to fit 1/2 gallon ice creams work
wonderfully to house them.