Originally Posted by Nylex
You only need one swap partition, since only one distro will be in use at any given time.
Since, as Nylex
says, you don't use both distros at once, you don't need to make it larger to accommodate 2.
If you think they have different swap space requirements, size it for the larger.
The old rule of thumb was 2 times RAM, nothing to do w/ the distro, only the hardware. OTOH, the last time I looked, MEPIS was recommending 1 gig for power users.