That's assuming that you can, or that it's practical.
My rig consists of a (beloved to the point of death) 17" MBP with 2 750GB spinners in RAID 0 (took out the optical drive). I'm not too sure that you can re-partition the RAID setup. I also have a Mid 2012, maxed-out iMac 27".
Regardless, if you're techie enough to create a secondary (or more) partition, then you have a spare drive lying around somewhere (I know, I'm assuming too).
This also introduces flexibility, as you can test out the release with different machines, and not have to do a damn thing to your existing, pristine systems. Just hold the Option key when booting and select your external.
Pretty simple stuff indeed.