A good place to start is to reference the appropriate tire inflation chart to ensure your tire pressure is safe for the load.
Sample Michelin Inflation ChartI have not run through the procedure myself on my F-150, but here is the procedure I found referenced. I believe you will find this in the manual, but the manual neglects to mention you need a tool to identify each tire. Here is a link with the procedure.
2012 F-250 TPMS TrainingAnd lastly, here is the tool required to help train the tires.
ATEQ Tire Training ToolAs stated above I have not done this procedure myself on my truck, I had just done similar research. Please do your own homework to satisfy yourself that this will work for you. You may want to check with a local tire shop and they may help you out.
They make inflation charts for a reason. Seems to me you inflate to the load you are carrying. A buddy of mine was a fleet manager for 30 years and did the same thing on their rigs.
Good luck to you,
Stu