We purchased a Foley rotary blade grinder last fall . I was quit content doing it the old fashion way with the 4.5 hand held grinder .
Now I wouldn't go back . You can get the exact same angle every time plus it is a way more efficient way to sharpen blades .
At the same time I ordered this balancer / leveler from http://easternturf.ca/ The center section is on a bearing and also slides in and out and is magnetised
The balancer is very precise . The side that drops is the side you grind a little more off .
Looks like an Atomic blade off our 4300 D.
The lever works by moving the gauge so it almost touches and spin blade around to see if it's bent . I would do a few of them to get a base line for the blades . I'm also having great luck cold pressing my slightly bent blades back to spec . with the new bench press . Sure speeds things up when your throwing on blades every time their done mowing the course .