With a long bed, it is best to be full forward, straight side of the arms facing forward. This will put the hitch pin center ahead of axle center, but still add very little to front axle. Due to each FW height, pin box to ground, being different, hard to say on height adjustment. You will want 6"s plus between bed rail and bottom of trailer, so best to set hitch on the high side, rather than too low. That toy hlr should work out to using a mid height adjustment, but unless someone has the same truck/FW/hitch, an exact recommendation is not possible.
Another option, is to call B&W, as they do lots of hitch installs, and could give you an idea, as to distance from rear axle center, and their best guess on height. You will talk to a knowledgeable person.
It is not hard to readjust the arms on the B&W, so if you are too high/too low, it would not take long to drop the trailer and readjust. Take the few needed tools with you.
You have a great truck, and will love that B&W 3305!
Jerry