It will go higher and will also lean back quite a way. I would try to set the Madstad up the same as the stock screen as regards angle and height, the spend a few hoursgoing a bit, stopping, adjusting a bit, going more, etc. You may find that the best position is higher and angled back quite a bit.
The mirror extenders will allow you to angle the screen back more than is possible without them..
Hope this helps.