Right or wrong I have never set any of my bikes to idle.
I always set them so they cut out unless there is a little weight on the throttle.
You should never let a Commando idle on start up because it kills the camshaft.
And once it is running I always found it safer to keep my hand on the throttle keeping the bike alive and ready to get out of the way of the idiot behind me who wasn't stopping fast enough at the lights.
As has been mentioned it's vital to generate sufficient oil pressure at all engine speeds hence the importance of correct calibration of the pressure relief valve. A good pump should produce approx. 20psi at idle with a hot engine. I know M Hemmings and others recommend shimming the valve so it rattles when shaken. This method tells you absolutely nothing about what pressure the valve opens at. Connecting a pressure gauge is the only way to establish prv opening pressure which should be between 45 and 55psi. engine hot.
Yeah, I agree. The priority is high enough engine idle speed to generate sufficient oil pressure. The cams will then get enough lubrication from the oil spraying out of the con rod journals in addition to oil draining down the pushrod tunnels. Obviously if the pump is struggling to generate sufficient pressure at tickover then the lubrication system needs looking at.