After reading dozens of posts and the GD manual, I'm confused as to the proper CAT scale procedure.

GD manual says weigh trailer alone, then truck and trailer while hitched, and finally trailer only while still hitched.

Another method I've read is truck and trailer hitched (each axle set on different pad), and truck alone.

Another method I've read is truck alone, truck and trailer hitched with WDH engaged, and truck and trailer with WDH disengaged.

What's the right way to do this?

Thanks