As part of a long running saga where the oil pressure light came on from time to time on my 501 New York I ended up first swapping the oil pressure switch twice and then doing a bunch of other things to try and make sense of what was happening and whether my engine was stressed and losing oil pressure somehow.
I've bought a 0 to 100 psi analogue oil pressure switch which has an 1/8 NPT thread (a very very fine thread) and an adapter (M12 x 1.5mm).
I ran the electric start with the kill switch on until I saw pressure readings, then started the bike as normal. The reading from cold at idle speed is around 58 psi. As the engine warmed and as I reved the engine in neutral the reading varied from roughly 50 to 70 psi. On the New York (and Excalibur presumably) the left footrest mount clashes with the oil pressure pipe, so I've got the footrest bracket unbolted and loose during these measurements. This means a road test isn't practical until/unless I adapt the footrest bracket somehow.
I'll add more info to this as and when I have it.
PS: These measurements may apply to any of the air-cooled V twin engines.