eagle.
I have no idea what you are refering to.
Lower the lever until the aerodynamic forces have an accelerating effect on the NR.
You are now in auto.
End of.
You can now turn off the engines and pull wingovers and bunts and spot turns or accelerate to Vmax to your hearts content as long as you raise or lower the lever to maintain Nr in the correct bracket.
You are just plain wrong about needing many hundreds of feet to establish in a stable datum type auto.