This is where autocad is a great tool. Draw it and print full scale. check
paper against part.

From there, you have all your holes centers and diameters. use a center
drill or spot drill (my favorite) then drill each point. A CNC machine is
best Grin, but a DRO works too. Do your milling at the same time.

Karl

P.S. Find me a deal on a Leblond servo shift and I'll make the parts for
you.