A quick method we us in Australia to calibrate with the 9750, works well with wheat, is that the grain tank when full is 10,000L or 10 ton if filled full of water. Start the calibration with an empty bin and harvest till full but not overflowing. Multiply your hectalitre weight on your grain docket of what the grain is weighing by 10,000 and this will give you an approx kg to enter into calibration.
Probably not as easy using acres and pounds but will give a 5% -/+ starting point if you are having problems adjusting scale number