Should this work?

1) I have a clean install of Hardy Server on /dev/sda6, with the swap on /dev/sda5.
2) I backed up the /dev/sda6 partition using TrueImage and then restored it to /dev/sda7 and /dev/sda8

I want to be able to use GRUB boot from one of these 3 (currently identical) partitions. Should this work? If so, what do I have to do to Grub or fstab or whatever to choose the active installation? The other 2 unused partitions can remain unmounted.

My intention is to play with 3 different server configs, including the addition of Mythbuntu on 1 of them and ubuntu-desktop on the other, until I figure out which one is best for me.