Question: I would like to buy only 4 capacitors like this:
750pF
1600VDC
500VAC
5% tolerance

I only find it on mouser but MOQ is 2'000; almost same as me !
How I can deal with that? Should I try to find 2 capaciters totalizing 750pF and wire them in parallel ?

Thank you

Answer: 
Try looking at parts with higher voltage ratings (when filling out the selection form select ranges)

a more durable capacitor should not adversely effect the operation of your circuit.

I found one on mousers site that was available in singles.
> 
> Should I try to find 2 capaciters totalizing 750pF and wire them in parallel ?
> 
> 
> 

Depends. I'll go with: no, unless you know what the job of these capacitors is, and what tolerance that allows, and how much voltage might built up if the connection of either of those isn't as good as the other.