I would take DL in F. I would think that WN has another added negative component which is the open seating - you can't know your seat ahead and there's a crush of people boarding based on their letter and if you wait to board at the end you'll end up with a middle seat in the back which is probably not ideal.

If you book DL F you can opt to be the last person to board and then just get on and take your single seat and minimize time on the plane.