My advice would be just to bite the bullet and go for two SFS partitions.

Although a full size FFS partition on an SSD would also be tempting. Revalidation is an extreme pain on modern-sized hard drives, but it should be really quick on SSD. Just keep in mind that disk recovery tools wouldn't work on it...

Edit: assuming the link that Andreas posted is right about FFS2. Has anyone ever tried huge partitions on it?

[ Edited by KennyR 29.10.2018 - 12:58 ]