hi i think we s/b considering engine unloading in the airalways thought you will pick up 1000 rpm in the air -over the rpm tached on the ground- but just lately was told could be as much as 2000 rpm- so this will also effect the engines break in- as the engine in the air is now performing in the rpm range it s/b- which is not the same as on the bench- more rpms produce more power and heat- this will be allowing the engine to break in and run under the actual conditions you will be dealing with in your daily flying- so get the engine into the air as soon as it will hold a good idle and a good top end rpm-the time it takes to get reliable needle valve settings will vary with a given brand of engine-os needs little time(one tank ) -while my 51 super tiger required the most (4 tanks )i add a small amount of castor oil to my brake in tanks- to help smooth the metal surfaces-i have done a lot of engine rebuilding over the years-and find the straight syn fuels (morgan-green ) to cause much more wear (than morgan omega -pink- -that has some castor oil )