Thank you, Gary, for your reply.
Fortunately, a slightly distressed look on the walls is what we are after, so some waviness will be okay.
My intension is to put 2 coats:
1st rough coat being Lime putty, 1mm sand & white Portland Cement.
2nd coat being Lime putty & .5mm sand., mixed with pigment for a faint ocherish color
I want a textured, not smooth finish, like the intonacco layer of a fresco.
My question is: has anyone worked over drywall with plaster, and should I cover the wall with a lathe mesh, and will a fiberglass mesh work or should I use metal?

Harveyk