I did not have any of the metal lathe mesh for my ceiling. I just used a prybar and a hammer, using the prybar as a cutter. You could use a oscillating cutter to cut the seam to get the old rocklathe out.
__________________ Ren: Now listen, Cadet. I've got a job for you. See this button? Ren: Don't touch it! It's the History Eraser button, you fool! Stimpy: So what'll happen? Ren: That's just it. We don't know. Maybe something bad, maybe something good. I guess we'll never know, 'cause you're going to guard it. You won't touch it, will you?