Shop ceiling dilemma

So here is the deal – my carport has looked the same since I redid the 1 bay outbuilding into a garage with a carport – for my boat.

Open with my garden and automotive chemicals. Well this spring I sold the boat and it is time to finish the shop by closing it in.

The outside is finished waiting insulation and an insulated steel door install. Sometime this fall when the door is in, I’ll finish the trim and stain it to match the original siding. The problem I confronted is the ceiling in the new building.
I cannot handle sheet goods by myself and I have no access to help. Whatever I do I pay for or do myself. When I priced installation of some type of sheet good, sheetrock, OSB, T-111, even ½” plywood, the prices were very similar. I started zeroing in on pine T&G because I have worked with it before, it was light weight, and my tools like working with it. I found some good stuff at the local lumberyard and while I was at it I bought a very large bundle of reject. I have lots of windows to work around on the walls and the reject will come in handy.

I have actually finished it now but I wanted to show this picture so you could get a sense of what it looks like while iI am working it. My seams are OK and my joints are clean. The original plan was to fill the screw holes(I hung the boards with screws), fill any real gaps and paint it some lite colored reflective paint. With the old siding on the back wall the place needs reflective lite. My helpers are held in place with 2 2” square drive finish screws. I move the helpers around as needed for the install. I was surprised at how small a hole they left when I moved the helpers.

But as I said, the seams and joints are good, the helper holes are almost unnoticeable, screw heads are also very hard to spot unless you are specifically looking for them. The lazy side of me says forget the paint period and live with it. Option 2 is find something to spray on it that will retard the natural darkening of the wood. I could go with the original plan but I fear the stuff will have to be brushed and I would rather not do that. And I want to do whatever is going to happen before the overhead door and lites are installed. And it has to be closed in from the weather by the end of October. After all it is just the ceiling for a shop so wood is OK.

Anyway, looking for suggestions for an easy answer to my ceiling dilemma. specifically whether it is even worth the trouble trying to find an aging retardant.