Quoting Graham King: I have always used 4 in any car, to be specific in the 7, I use a limit of 3-3500 RPM until the oil temp reaches ~ 60 degrees, then 4500 until it reaches approx 80 degrees, then I give it full beans. I'm not anal about it but use those as general guidelines. Water temp is largely irrelevant in all this.
Graham.
Exactly what I do. Although I watch the water come up first, check it stabilises then flick the switch to watch the oil come up. When it's up at 80 degrees, I flick back to water and monitor that to check it's not overheating. Yes, I know it's a little bit anal 😬