Depending on the type of engine, the viscosity may not influence the correct pressure reading. The installation and/or commissioning guide may have your answer. I woukd expect something in the neighborhood of 850kPa gage.
okay, I made a mistake - the figure I gave was absolute, not gage pressure, and it is pre-filter. Post-filter would be 100kPA lower with a dirty filter.
The engine manufacturer will specify an acceptable range of oil pressure. As long as your high load/hot weather readings do not fall outside of this range you should be fine and your warranty should be valid.