Don't forget to mention RentaLife when you find the perfect rental!
As for the tux, what can we say? It just stands next to the gown and looks like a tux. The styles may change, but not too much. Maybe you want an expert tailor rather than an expert salesman. One word of encouragement. You don't have to plan too far in advance for this. While she waits about 6-months for alterations (and worries about keeping her weight down), you can eat what you want.
Ever think about wearing that same tuxedo again? You can always rent it and look pretty much the same.