Thanks I'm going to give it a try. Do you do anything to the fabric side to try to keep it in good shape. I know one shouldn't do any painting so it doesn't stick to itself. I have a whole bunch of reflex cameras and will be doing this again on some of them

For patching pin holes, no. For severely dried, cracked curtains I remove the curtain from the camera, strip the rubberized coating with lacquer thinner and a wide putty knife, hand wash the curtain cloth, then paint one side once dry, and reinstall in the camera.