several years ago I remade all the headliner on my boat with a T & G plastic beaded product as shown. I found it at the local big box home improvement store. They may still carry a similar product.
The ceilings are built with laminated 'beams' on 13" centers. These provide a 2.5" space for wiring etc. Caps for these beams are simply screwed wood battens.
I cut these pieces to length, interlocked the pieces which are held in place by the battens. I also put a dab of clear caulk on the end of each row to keep things in place.
Should I need to get into the ceiling it is a rather easy matter of removing a batten or two then unlocking the row of headliner pieces.
These came with a semi-gloss white finish which nicely fits with the look we wanted.
The Admiral regularly says this was one of the best cosmetic upgrades done to the boat.