This repo proposes a free CAD model of a solar finder for an amateur atronomer telescope, adpated for skywatcher finder mounting.
It has not yet been printed nor tested, print it and use it at your own risk ! (that said I would be happy to have some feedback ! In particular I am not sure the dimensions of dovetail are optimal)
You can download the stl file and print it. You can also download the source model and edit it with openScad : http://www.openscad.org/