I would mention something that's not exactly on topic but I think it should be mentioned here...
For a reliability point of view, is usually safer to put several caps in parallel than several caps in series, also, as with series caps you need balancing resistors the leakage is a problem, through the resistors this is, in parallel caps you don't need that.
Now, you need several caps to fit in some space X amount of capacitance for X voltage, so in the same package you can get higher voltage lower capacitance and end with a similar result, with all the caps rated for the desired voltage and get to the desired capacitance.
I do know it could be easier or cheaper to get one or the other, let's go for 1F 5V and 10mF 50V caps, let's go to mouser, cheapest ones, for 10, $2.85 for the 10mF 50V, $3.55 1F 5V... YMMV depending on the ratings. I also didn't compared sizes, this 10mF 50V ones are likely bigger than the 1F 5V
JS