If you are worried about gyno, then that is kind of a shity cycle in my opinion. Not only do you have to worry about estrogen-induced gyno, but by adding the Deca, you know have progesterone gyno to ponder as well. Even if you add Nolvadex, it won't matter if you are prone to Progesterone-induced gyno from the Deca, since 'dex has no effect on blocking those effects.
That doesn't mean that you will get the gyno from either of them though. Some guys are more prone to it than others. I'm just saying, that if you were "so worried" about it, then why did you one-go with THAT cycle, and two-not add at LEAST the Nolvadex to ease at least some of your worries? Makes no sense.