One thing to avoid for good engine health is bogging down/stalling. The journal bearings hate to run at low speed & high torque conditions, due to a breakdown in the hydrodynamic film thickness. As the film thickness is reduced, metal to metal contact between the high spots starts to occur, causing increased heat and wear.
Looking at the characteristic curves supplied by rbargeron, maybe try running the engine at a higher speed than you have - say 1800 - 2000 RPM, even if you don't need the HP or torque. My reasoning is twofold:
First, as jaotguy noted, the water pump will be doing a better job getting the heat out of the engine and into the radiator. A well cooled engine is a happy engine.
Second, as rbargeron notes, the engine torque curve has a peak at the low end. This can be used by an operator to good advantage by taking note of engine speed in response to increasing load. As engine speed starts to drop off, torque increases and the engine can maintain the load. After the engine passes the point of max torque, though, increasing load will rapidly bog down the engine. Running well above the peak gives you time to react to increasing load and decreasing engine speed before the engine bogs down or stalls. Your journal bearings will thank you.
