you need a commercial building installation company to supply if not install. It’s just larger elements than residential, same principals. This stuff is pretty easy, there is a large industry geared just for these types of buildings with standard parts for this.
They will provide you commonly...
the dimension you describe, from lock center to bottom of a pull handle (throughbolt), is called the throughbolt dimension. yes most seem to be above 8.25, but some manufacturers offer down to 7 or less. many offer adjustable bottom throughbolt position, via vertically sliding bolt hidden...