I expect Romo to see just enough action to shake loose from the rust and find whatever might be missing due to an absence of live action. The staff will likely want to protect him from unnecessary punishment and preserve his well-being as much as possible for the season opener. I'd honestly be a little bit surprised if he were to see a full first half of action.
Dak, on the other hand, needs all the live game pro experience he can accumulate. There isn't a better experience for him than to come up against the Seattle defense. He'll benefit from what they'll offer in terms of making him compete mentally and physically against capable opposition. I'm anticipating we'll start seeing him about halfway through the 2nd quarter.