Motor capacitors

Look what I bought:
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A brand new set of motor capacitors. All are rated at 450V and have 10 uF (4 pcs), 40 uF (1 pc) and 100 uF (3 pcs). They are designed as startup-capacitors for electric motors, but I intend to use them for powering my lasers. Although they are rated at 450V, I'm going to charge them at 1000V. My friend Bogdan already tested them at this voltage and they didn't blow up in his face, so it should be ok.
The small ones (10 uF) will be used in a voltage multiplier for charging te other caps. They will rise the voltage from 220 V to 880 V (I think I should add two more, to reach 1320 V, but that's 3 times more the rating of the caps and I'm a little afraid to do it).
The medium capacitor (40 uF) can hold a carge of 20 J at 1000V and should be ok for powering the SSY-1.
Now the interesting part: the largest capacitors can hold 3 x 50 J and should be just fine for powering the larger laser.
Unfortunately Bogdan tested these capacitors and they didn't discharge fast enough so his SSY-1 couldn't lase. On the other hand, on Sam's page I found an article stating that they should work just fine. I don't know what to say... I'll perform some tests and update this post.