[Amps] KW Rated Low Pass Filter Caps?

[doc]

I need to access the gathered wisdom here ...

I am building a switched low pass filter for my full legal
160-10M solid state amp (1500W).

I have access to a number of free (from a friend) older surplus
Mica caps rated at 2,500V (a few are 3KV and 5KV).

I also stumbled across  unionel.com  where they have 1KV
Ceramic Disk caps for $0.32 each.

Questions:

1.  Are the Micas likely to have drifted significantly in
value over time?

2.  Is 2,500V a sufficient rating for this application?

3.  Are series-stacked Ceramic Disk caps of the same value
(e.g. four 100pF caps for a 4KV rating) a good alternative
to achieve high power handling capacity?

4.  Are Micas and Ceramics of the same capacitance, voltage
rating, and tolerance % equivalent components in this app?

-- 
Thanks! & 73, doc kd4e
A blessed and joy-filled New Year to all!

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