Low oil pressure makes me nervous

With the current 40 wt Quaker State, the hot oil pressure at idle right now is halfway between zero and the first graduation on the factory oil pressure gauge. At speed it doubles to the first graduation when hot (except going up that long, steep grade as I explained above when it was reading the same as at hot idle). A second (aftermarket) oil pressure gauge would be fine, but the dash gauge is working and like I said above, all factory gauges have been restored and function.