Since you just examined your oil pickup tube, you have a good idea of its location and where it points inside the sump, i.e., in the middle, pointing left, right, front, or rear. I suggest that you keep track of when you lose oil pressure, and analyze conditions when it occurs, like left/right turns, under acceleration, compression, braking, etc. You may also want to check if any other electrical function stops momentarily at the same time, which may indicate a bad ground. Additional ground wires are cheap and easy to run. Since it happens so fast, a right-seater may help with observation by looking at any other electric gauges.
If you can't find the fault quickly, you may want to consider pulling the oil pan next. I installed a welded/gusseted after-market oil pickup tube in mine, since Subis had some problems with cracking tubes. Since you have 2 independent sensors with separate gauges, and both are in agreement, the gauges are likely not the fault. Oil pumps themselves are reliable and long-lasting, so that may be the last thing to check.