[Amps] Pi L networks

[Steve Flood]

Here is what I've derived for my 160 amp for a 2700-ohm plate load.

Ctune 250pF
Cload 1500 pF
Lpi 39 uH
Lel 9.1 uH

Based on my previous questions regarding making room for everything and the 
answers received,

My homebrew Ctune is 9" long.  I built it at 0.16" plate spacing for 5400 
volts breakdown (which is twice my plate voltage of 2700v).  I did that 
because of what I read in the Orr handbook.  However, using a couple 
different Pi-L software calculators, the peak voltage at Ctune is only about 
2500.  Do I really need twice the plate voltage rating at Ctune?

Steve, KK7UV