Sounds like you've got it pretty close to right. The washers referred to by Dutchmen Sport are spacers used to angle the hitch head. They should be shown in the instructions.
One thing I would mention is that while trailer tongue weight counts as cargo, cargo in the truck does not count as tongue weight. Your trailer probably has an actual loaded tongue weight of about 750 lb, so 1000 lb bars should work fine.
But yeah, hitch up and take a ride. I suspect you'll be just fine.
Edit: according to these instructions, those big bolts want 260 ft lb of torque. The diagram shows the spacer washers as #12b.
Clicky
