I play Gro myself, and I have found the Deadguy-Gro matchup to be easily in Gro's favor. Why? Because your game vs. UGw Gro depends on keeping them off white. They run tons of draw, and at least 9 ways to get white mana, as opposed to your 8 land destruction spells and 4 Bobs. I have never been successfully kept off white mana, and Enforcer is good game. The UGr Gro matchup, however, is absolutely horrid for you. 4x Nimble Mongoose are killable only in combat, and they're in green, the second biggest color. Running more removal than UGw Gro spells trouble for you as well.