I think I will throw caution to the winds and see how I go with a single torque down. I will advise what happens.
It is nice of you to use your bike in this experiment, and let us know what happens.
Be aware though that it is more than the head gasket that you might lose. I was once shown an extremely mashed piston, and was told it was the result of carelessness in not retorquing. The opinion was that the air leak therein resulting did the damage.
Yes, well I could just follow the good advice here, but it is a bit of an experiment too. I am modifying my ideas all the time and later this week, when all is done, I will report back. At the moment I have moved one step closer to Dr Healy's position and willdo one retorque after the initial engine run.
I also have in mind some radical views like greasing the head bolt threads, oiling between the head bolt and the washer prior to torquing, and increasing the torque on the 3/8 bolts to 25ft/lbs and the 5/16 bolt to 18ft/lbs
I am even considering a tenth bolt hole, or alternatively a plate on the ninth to cover an area where the tenth would go.
And so it goes on. RR