Here is a shot of my D180 Dynon with the trim indicator circled.
Mangy.jpg
I have a Ray Allen servo controlling my trim tab. This is using the internal feedback circuitry in the unit. The white arrows show the position of the tab in it's throw, the vertical rectangle, and the green line is the position I assigned as "neutral". There is also a mark (not easily seen in the photo) that indicates a "takeoff" position.