silent running

Now I've got my oil pressure gauge in, I'm starting to notice patterns. 10W40 Motul 300V oil. Solid 6 bar pressure when cold, consistent 5 bar when over 3000 revs at 85 degrees C, and hot idle at 1.5 bar. I'm happy enough with that and don't think I'll be changing to 15w50 as the pressure seems good to me.

I've got my low warning set at 1 bar, mainly because it idles at fairly low pressure and I don't want the alarm going off the whole time. When I take it over to the 'Ring later in the year, I want the thing to tell me straight away if there's a problem. At what pressure should I set the warning? What would be a good minimum oil pressure that I'd want to see, bearing in mind I'm expecting the oil to get a lot warmer than it would normally see in everyday use. The most I can get it to is 90 degrees when I'm really caning it on the road. Obviously on the track it'll be a totally different environment - full throttle or full brakes the whole time is the aim.

So at what oil pressure is the engine not being lubricated properly when under full load for long periods? 3 bar? 4 bar? 5 bar?