That all sounds about right. It can be hard to get the front end to come down on a full size truck.
Now tow with it. If it doesn't push you around in the lane then your good to go. If you do find the truck is suddenly moved from one place in your alne to another, tighten up the spring bars a little more. Keep in mind that two washers equal 1 link. Make any adjustments using very small increments. That means try adding 1 washer if it doesn't handle right.
I wouldn't want to drill 8 holes either! I would try one bolt at each end and see how it works out.
