I had a little larger pole barn w 14' walls built and have been doing all the finish work myself, electrical, plumbing,interior and insulation, but not the concrete work. Just had 5000+ sq.ft. poured and finished between the driveway and shop.
I decided that I would panel the ceiling and walls with the same siding we used outside and had to come up with some thing to fasten to and hold my insulation. I was able to locate up in the Mennonite area a little north of me, an individual that has a working saw mill. I spec'd out 1" net x 6" net both southern pine and tulip popular, placed this horizontally on 23" centers, insulation is only 23" wide and stapled it every 2 courses.
On the ceiling I placed the "Battens" on 24" perpendicular to the trusses that are are on 48" centers and laid insulation (R-38) across the battens. No real sagging but when completed the metal siding will support what might be below the battens.
Now to kind of answer what you had posted, with the battens providing the attachment and backing of the metal siding, I could run 14' long pieces vertically and use spacing to attach cabinets and etc, to,. but I will use sheet rock and plywood to the battens for those areas I know where a flat surface would work best. I plan on just butting my siding to the rock or ply, may use a J trim or some kind of edge molding to finish it off.