Very Low Oil Pressure in New Engine

You have to have the engine turned to exactly the right spot for oil to come out of the holes that feed the rocker arms and it's a different spot for each side. It doesn't come out continuously so ignore that as a problem. Did you cut open the oil filter for an inspection yet? That'll tell you if it's a major problem or not. If there's metal crap in it you know something catastrophic happened. If not it's possible the oil pump relief valve stuck open. Your mention that the oil pressure reached nearly 90 psi during break-in doesn't sound right because the relief valve should not have ever let that happen. Did you disassemble the oil pump for a cleaning and inspection before installing it? You should always do that cause you wouldn't believe the lousy quality control in some factories. Do it as fast as possible so they can sell another seems to be the motto of today.