I run 10w30 durablend and my cheapo electric oil pressure gauge says 0 psi at idle when warmed up. The dash light doesn't come on though.
I got that with the autometer mech that was stolen. Dummy light never came on, but it would drop from 15psi to 0psi at idle (extremely fast, I might add). FYI most gauges aren't that great on the outter 30% of their range, meaning 0-15 and 85-100 range is probably over 5-10% from accurate. Autocrap gauge needles are probably not set properly anyways, so take the readings with a grain of salt. For best results, calibrate your own honeywell pressure sensor, then measure the voltage to check your psi.
Use the gauge for CHANGES, not absolute values.My built z6 w/fresh ported/devcon'd oil pump would drop below 10psi at idle with an autometer gauge when it got very hot, and below 40psi at 3k on a looong trip. I changed from 10w-30 to 10w-40 and it's a lot better. That's running 16psi every day I drive it, no issues. I don't stick to a particular brand because I'm cheap and it can help reduce certain deposits.
The trade-off with thicker oil is it doesn't flow as well. Oil pressure isn't worth shit if your oil doesn't want to go where it's needed.