5th wheel height

My door header on my barn was too low for my Grand design so I raised the header. I worked construction (ironworker) for 37 years and reworked lots of trusses especially in car plants where extra headroom was needed. It is a relatively simple procedure to put in a new header above your existing by sandwiching in the truss and securing the diagonals and plumb posts to the new header at the level you want. Add on to the jambs and side posts, then remove the old header and section of truss below the new header. This will allow room for a rollup door spring and door housing on the inside as long as your other trusses have adequate bottom chord clearance for your new 5th wheel.