Now I wouldn't touch him at all. It would be hard enough to get two creatures out after summoning him, and then he still only sticks around if you can keep up a constant supply of creatures. If you are able to throw out that many creatures, there are more productive uses for them than feeding some 9/9 trampler. For three more mana (which is a lot, but so is losing flying and the somewhat costly regeneration ability along with gaining an exponentially worse upkeep and losing all of your creatures when it comes into play), I can get Devouring Strossus, which will in all likelihood outlast my opponent...