Yea you seem good to go the only stipulation with Crossfire/Sli configuration is making sure that the ram count is the same between both cards. I would place the 3 slot card on the bottom and the 2 slot on top if you have the room for the cards.
Yes, I considered that, and I am going to do just that. Both card have same amount of ram. Maybe just maybe I will be able to find another Sapphire card, if not this is backup plan