Delrin parts

I have been given some step files from someone who wants some parts making from Delrin.
He wants 8 of this part. The first thing is to cut the circle out of the middle.
I haven't got the Delrin, yet, so I am having a go with some wood that I have found in the workshop.

Next to clear the lower level with a pocket operation.
I made the shapes to cut by doing Edge to Sketch, on some circular edges, then making circles with "centre" and "end" ticked in "digitizing". Then I made the circles to sketches, then to faces. Then I subtracted one face from another and made another face from a sketch across the middle, and subtractacted that. Finally I did Face to Sketch to get me the sketches I wanted.
I am doing it all with my 3mm slot drill, so I don't have to set the z height of the tool again. This does mean a lot of tool path, though.