Turning the pump faster and using a thicker oil may not give the results your looking for. I'm no expert with the micro systems but I think faster pump speed and thicker oil = cavitation and faster wear on pump gear shafts.
Correct me if I'm wrong but , im pretty sure the pump has no bearings or bushings to handle higher speeds?
Kinda like using a grinding disc rated at 5,000 rpm and using it at 15,000 rpm???
Mario