B&W Companion F350 SD DRW 8' Bed - what did you end up as your bolts to use?

[Flintlock]

Wondering if a F350 Super Duty DRW owner who uses the new B&W Companion Hitch could tell me which bolt holes they ended up using to install the arms. I'm just looking for a first guesstimate to work with.
I have a full bed so from what I can glean from readings I can set the arms all the way to the back, the height would be "the middle". I'm fully aware I'll have to fiddle with it no doubt, just curious as a first stab knowing what works for others.
Just info gathering for the trailer pickup day, this isn't my first rodeo for RVing but first 5th wheel, so don't want to be a total moron when I go get it :-)