G?day Adrene.
The easiest & cheapest fabric to use for painting, is Calico.
Buy it on a roll from a upholstery suppliers, as either unbleached calico, which is cheaper, they is normally use for the under neath of sofas & arm chairs.
Depending on the height & width you need, as either a Tab or one piece Traveller curtain?
Either way roll it out, so the fabrics length is used laterally, rather than horizontal panels. Using a 2 part Epoxy Glue, the panel strips can be joined together as a lap over. Attempt to work out which way they will hang & determine the head & tail of each strip panel edge. Place the tail edge over the head edge on each joint, so the paint won?t collect & be reattained in the seam.
With the seams running laterally across the stage, they can be painted as a mortar course & covered up.
When the curtain is produced, reinforce the head of it with hessian or burlap webbing strip, which can also be epoxy glued on. Obtain a cheap canvas eyelet applicator & punch in eyelets evenly access the length of the header webbing. These only have to be about 1? to 18?? apart, depending on the curtains size.
With the rows of bricks, lay the curtain flat on the stage & use a Chalk Liner, to mark the lateral mortar lines first. Then use ordinary water based paint.
From your post I gather you are going to use an upstage Tab track, rather than your House Rag?s.
If so wind up some cordage on to a piece of ply & cut the cord down one side of the ply. You will end up with short cords to use for ties at the curtain header. Each cord would need to be about 3? long.
Fold the tie cord in half forming a loop in the centre, then push the loop through the eyelet.  With the 2 cut ends of the cord, put them through the centre of the loop. This makes what is known as a ?Larks head? knot on the eyelet, leaving the 2 cut cord ends as pig tail ties to tie off the curtain to each of the tabs on the track. Use an ordinary ?Bow? knot that you tie your shoes up with, because it makes it quicker to undo when the curtain is to be removed, by just pulling one tail end of the Bow to untie.
You can fold a pocket in the tail of curtain to put a chain in, if it needs extra weight to dead hang properly.
The water base paint won?t crack & will fold with the fabric.
 

 

Also...about the bricks....mark out straight lines. Don't guess..make sure they are very level, plumb and true. What makes brick look like brick is the uniform lines.  Then get a sponge that is the size of a brick....4" x 12"  3" x 8" .....measure a real brick.   Dip the sponge in paint...wipe off excess and stencil the bricks..just make sure you stay level and square.

Perpendicular seams are a major problem, because with the downward weight of the length of the fabric,. Will cause it to stretch unevenly & pucker. However with the panels hanging horizontally, there is less downward fabric weight, in the width between each panels seam.
Perpendicular panels sewn together, rather than glued, are even worse of course.

I have a couple more quick questions:

Joe, when you say ",,,use ordinary water based paint", do you know if
that's what we call "latex" paint in America?

Also, is "calico" the same as "muslin" would be there?

Thanks again,

Adrene

 Please do Joan!
I tend to forget that we are separated by a common language!
Your right that we call Latex ?water based? or ?Plastic Paint? as a generic term. Which the UK term as being ?Emulsion? paint.
I used bed sheets for drops, but I like the idea of the Table Cloths!
However when I?m skinning flats, I use raw unbleached cotton calico [muslin] because it will shrink more when water is applied, rather than any bleached cotton or fire retardant added fabric, as this will pre shrink it. But for Drops this is not a critical requirement.
However with storing the c drop cloths, I find it easier to roll them up on an old carpet cardboard roller or PVC sewage pipe. Dead hanging or Fly them out, is preferable of course, if you have the space &/or Fly Loft.
Using a Proprietary Brand Plastic Primer works, but in most cases, I find the easiest & cheapest, is ?Wallpaper Size? which is just as good. I just get the ordinary cold water ?Size?, but it has been suggested on another forum. To use the Hot water type for better results. However this is quite a business to keep the pot of Size simmering on a small stove or burner, for it to remain hot & pliable. Because the Hot Size sets while cooling & you end up with a filled pot of a smelly lump of solid Size. Cold Size takes a lot longer to set & is just as solid & smelly, if left out over night. The venue will smell like a load of putrid unwashed socks & everyone will be checking that the smell is not from themselves! however just mix in boiling water & it will render down to be able to use again. Then you don?t have to spray any more air freshener!
Best way is get rid of any left over or seal it up in an air tight container. The same as ?Casein Paint? [a Milk & Egg derived product paint, used for Scrim painting] which goes off, faster than  a dead ?Prawn? in the sun!
Another way to bond the cloths surface is use ?Whitener? which comes in a powder for & can be mixed with water, this is good for Scenic & detailed painting of cloths, which gives a white bond base on the cloth to work with.