I agree, I'll fill up the reservoirs. The spec'd OM-13 is a very thin hydraulic oil, with an ISO viscosity of 12-13 cS. These lighter oils are expensive, so I think I'll use the common ISO 32 hydraulic oil. I can get 20 litres for $50, so about $200 total. That's no problem. And we'll only be out $200 if it all leaks out.
Malcolm