I've got t3i and it took a while to get It to fit right, especially considering on the Merlin cookbook website the user specifications vary a lot.
I actually re calibrated it just today! However right now I forget the settings. However it has a finish weight in the middle, and at the bottom a start, mid, and finish weight. I also think the arc is at it's smallest. Definitely gos on N. and is about a number 1 on the top. Ill give it a check tomorrow!