Get the Ford power drivers seat, you will not regret it. The adjustability is almost limitless and it enables almost anyone to get {and stay}, very comfortable even on long days.
If you are over 6' tall or the first number when you get on the scale is larger than 1 you may find the Ford C's {E-350/450}, a little snug and the power seat will help a lot. Also know that if you have a slide that comes in directly behind the drivers seat your ability to slide the seat back and/or recline will probably be limited.
:C