Help a pasty white person avoid a sunburn at the game

I will be in Seattle on 7/19 and want to watch the M’s play the Astros. I think my wife said the game at 6:30. Where is the best place to sit to limit sun exposure? I don’t know anything about when they may or may bot retract the roof, so it might be a moot point.

Also, for anyone in the know, are the stadium tours worth it?