This is moment when you just gotta commit and go do it. Blaze a new trail. Become the King Ranch seat guy.
Speaking from experience with putting seats in the Eseries that weren't designed to go there... Take a look at the Body Builder's layout book for the Eseries and Fseries...
There's a page in those docs that shows seating position dimensions. The Eseries seat base is offset (mounts relative to the steering wheel center). Not only does it feel super awkward if the seating position is off, it's also important to be in the right spot relative to the airbag.