As to your diagram, since you are using the 'Pressure Equalization Membrane', the 'Low Port' on the 'MPS Fill Sensor' should be open to atmosphere, NOT closed. In this way you are using atmosphere as the return line between the top of the reservoir and the 'Low Port'.

With 170mm water column the MPS 200 sounds right.

I do not know what pressure you will see across the pump, but having a maximum allowance on the reservoir may not be indicative of your actual pressure. I know in the Dr. Drop manual, aquacompiter says not to go above 0.5 bar, but again, I do not know how that relates to real system pressures. Perhaps someone with experience will jump in.