The rest of the story...
For those who tuned in late, I'm replacing the power supply filters in a He athkit IT-11 capacitor checker. In the original circuit they are two 40-uF 350-V in series (to handle 600 V). I ordered a 20-uF 1-kV film capacitor to replace them.
Well, there just isn't room for that film capacitor under this chassis! So I had to resort to two 47-uF 450-V in series, like Heathkit's original.
There was debate in this thread about whether to add balancing resistors, a nd I didn't. John Larkin said "they take care of themselves." Indeed they do, sharing the voltage to within a few percent of equal.
I wonder if Mr. Larkin could explain further. Is there some effect that ma kes them equalize if they have different leakages to start with? I would e xpect the opposite, that the leakier one would carry a lower voltage and wo uld form less, causing the difference in leakage to increase -- but I might be wrong.
I am going to look back at the bleeder network and see if there's a good wa y to split it in half.