I know this isn't the answer you are looking for, and this sort of goes for any who are into the whole dual/triple booting thing...but why bother. I went through the whole wanting to dual boot Linux/Windows or dual boot 2 dsitrib of Linux but it was nothing more than just a slight dream. It never materialized. I have Linux on it's own separate PC and I couldn't imagine it any other way. Now, I do have a dual boot of Win2K and XP...but I have my reasons for that.
But if you're just in it to sample which you like or whatever, just try one for a while and see what you like...if you don't like it reformat and put on the other.