Haha..
This is the peak so it's going to be more important to work near maximal than it is to do sumos. But you're absolutely right...you can't get into sumos for the first time doing heavy singles. You hips and groin will definitely hate you for that. Doesn't seem like a good idea.
I'd just do conventionals. I'd be interested in what EC has to say. He has this new suggestion of posting on a dedicated thread at T-nation instead of e-mailing him. LOL...ain't gonna happen. I'd email him