Re: Are you a Hardwood Flooring Expert
Face nailing with rose-head or other cut nails would be better than gluing. Are they random-length with lots of shorts or nice long planks? You can't efficiently face nail (exposed nails anyway) the shorties. Looks too busy, takes too long (nails at ends of boards must be pre-drilled, though all nails can be pre-drilled which guarantees no splitting). Face-nailing has to go into joists, too, or the vertical nails will loosen right up and out of the plywood decking in no time.
When we make our own flooring, we always cut grooves and spline it together. Shiplapping is just not as reliable, and you will get edge split/tearout which spoils material. Putting a 1/4" groove down both edges (three-wing router bit) is a good mindless job for a helper. Then, rip some spline stock, dial it in by passing thru the planer and you're good to go. The greatest reason for splining is that with super-expensive reclaimed wood (we do a lot of restorations) you're not losing face width of 3/8" per course like from milling T&G's.
If you want rose-head nails, you won't be able to sand the floor, because you'd spoil the nails or have to set them awfully deep. If you were to use 1/4" plywood for splines you could blind nail through them (would be a problem with solid wood splines, I'm afraid-- will split out).
But if it's a cabin look, maybe pre-sanded or unsanded is okay?
Remove not the ancient landmark, which your fathers have set.