It would depend on what your target rate of application would be. It will also vary based on the mix of seed/fertilizer you are using and the type of sowing wheels that you have installed on the machine. The lower you target rate, the slower the shaft spins, the higher the target rate, the more rotations you will have when performing the calibration.
I like that!
How many times does the drum rotate for the first weight measurement?
It would depend on what your target rate of application would be. It will also vary based on the mix of seed/fertilizer you are using and the type of sowing wheels that you have installed on the machine. The lower you target rate, the slower the shaft spins, the higher the target rate, the more rotations you will have when performing the calibration.
With the twin bin would you be able to shut off 1/2 at a time, like a section control?
Yes, the 5.7 controller allows you to turn each half of the sowing wheel on or off, so you could use it like a section control.