Dove Tail Tool Sharpening ?

I am using the new dovetail tool along with my Supernova and powergip jaws. I am new at using this tools and have a few other questions - I have used them on the recess and on compression in making tennons. In compression it works fine and the tennon is turned off, sanded etc -. When i create a recess and use it (with the power grip jaws) i find i have to make the recess a bit deep in order for the flare on the jaws to seat well. It is not big deal and the tool works easy to create the angles for holding. I tried to make it shallow but it loses its holding power in the jaws. It also leaves some marks on the inside of the tennon that have to be sanded out later from the jaws tightening against the wood.
Being a bit new at making the recess i thought i would see how others are doing the recess

I would just freehand it duplicating the existing angle. Eventually it will probably get a little out of whack, at that point, scribe or mark with a sharpie the correct angle on the back and re-grind.