If you happen to be fortunate enough to have a Prius with a sunroof, does it open all the way in one step, or do you have to open it up most of the way, and then press the button again to open it up fully? Also, only if you happen to have a moment, I'm trying to figure out how far it is supposed to open. If you get a chance, can you measure the maximum "open" area from the inside? If not, I'm still interested in the answer to the question above. I'm most interested in the 2010 model year, but any Gen 3 info will be useful... please just indicate your model year in your reply. Thanks!