A good place to start is 160cm from pin top to pin top. You will also want to make sure your pins are set equidistant from the centerline of the shell. Since there is no reference point for the center, the best way to ensure this is to measure from the outside of the opposite seat track to the top of the pin, and make sure this value matches for each side.
If you are using a pitch meter, you want to calibrate your pitch meter at the deck between the threaded inserts where the rigger attaches. This is the location where the boat is parallel to the waterline. Put your level meter along the edge of the deck at this spot. We recommend a 5 degree stern pitch to start, and your oarlocks will come from Maas with the 5 degree bushings installed.
In general, if you have too much pitch your oars will tend to wash out; too little pitch and your oars will dig or dive at the catch.