Help alleviate my anxiety - engine was noisy on startup

Background - 1969 340 0.040 over, Purple stick with hydraulic lifters. On initial break-in (replaced 2 lifters because I dropped them), the engine ran quiet and well. 75-80 PSI oil pressure on a high volume, high pressure pump during break-in. 5 quarts oil with 1 pint zinc additive. Changed the oil, cut open the filter. No metal anywhere. Everything looks clean.

Fast forward to yesterday. The engine hasnt been run since break-in. I did change the oil (4 quarts with 1 pint zinc additive). Turned the engine over without starting to prime. Then started. We had a lot of valve train noise that largely went away in seconds (guessing not enough priming). However, there remained a very loud "clack" on the driver side. Pulled the driver valve cover to check valve train and watch it run. Had oil to the rockers, but not consistently.

We looked around for a reason. There was a not insignificant oil leak at the pressure switch. Sealed that up (I think we didnt tighten it the first time around). Also checked the oil level on the (original) dipstick. It was at the "add" line, so I dumped the remaining quart from the 5 quart jug into the engine. Fired it back up, and the loud clacking got softer until it was gone. I had consistent oil coming from the rockers. The only other thing I did was back off the timing, but I dont think that had anything to do with it.

**Unrelated, at idle (after fixing the two issues above), there is plenty of oil coming out of the rockers to get to the rocker and valve tips. Oil holes are in the top of the rockers. The inside of the valve covers were nearly dry. I dont think the oil hole on top shoots oil everywhere as some have suggested. Back on topic**

So now everything sounds and feels good. Can I assume it was a small lack of oil pressure or volume? I didnt run it long enough to get anything hot, so I think I am okay? I should probably watch the oil and filter for metal?