I can achieve 100% fill in a tapered horizontal joint, no recess and no mound, but I was told I should instead have the tiniest bit of a mound, and feather the mud back 10 inches from each tapered edge. What is the point of a tapered joint, if it's going to be treated like a butt joint? When applying a knockdown or orange peel texture, is that joint going to be visible after primed and painting the wall if it's a perfect fill in job flush with the drywall paper? I put a lot of effort in two of the rooms to sand, mud, sand, mud to get a perfectly smooth and flat joint and don't want to excess mud and taper the joints if it's unnecessary - but I also don't want to have a problem after primed and painted. Any input DIYers and Pros?

I'm refinishing my basement. It's basically suited although I don't rent it out or plan to I would like to finish it up to fire code between units. In the main room the prev owner ran 2x4 across the ceiling cross ways to the floor joists to run wire pipes etc. I'd like to be able to access it later if required without ripping down 5/8 drywall. Could anyone recommend a material I could finish with that could be accessed later without destruction but meet fire code? Thanks!