so can you do it with different partitions on one drive or do you need 2 physical drives?
also what boot manager seems to work the best?

thanks so much community i love you all!

Works on two partitions and two seperate drives.

You can use a third party utility, such as GRUB, or acronis boot selector. I like to just use the darwin boot screen, which can be edited by changing boot.plist. Search for that, if you want, it's the easiest solution.