Just to be
clear you want to re-rig your existing bi-parting Main to open as a
tableau, correct?
Can it be done? yeah.
It probably won't give you the results you want and it might possible damage you curtain. Most
tableau's are either made from lighter fabrics or they are rigged, from the beginning, to be able to resist the stresses that are kind of unique to the
tableau rigging. Increased number grommets, especially towards the center of the curtain are a must. For the best results you would need to remove the
track, add grommets to the first 6-8 feet of the center side of the curtain panels, add ties to the grommets, tie off to the
batten, then rig the trip lines to the back of the curtain. the best way to add the trip lines is to
plot out the path of the lines then select the number of points wear you want the
swag folds to happen, then sew on stainless rings at each
point. Then add rings to the bottom center corners and tie-off the trip lines. Rig pulleys to the outside ends of the
batten and run the lines back to a common
point left or right and/or rig them to spot blocks and run the whole thing from the
rail.
If your main is old you run the risk of it tearing at the points where you add the rings < I suggest
whipping them to seams between breadths so the stitches don't show through on the front of the curtain.> You also run the risk of pulling grommets through the
webbing because of the forces imposed on the center points of the curtain. Cotton
velour is going to drape differently than
IFR/polyesther and depending on the weight of the fabric you may or may not like the results.
None of this is hard it's just a lot of work.