I am posting a question. I have quite a selection of thread, have worked many samplers from basic thread, heavy and even yarns and silk. I get a curling effect that I don't want. Is my selection too tight of a twill? I have to constantly dangle the needle to get it right and it still curls.
It is because the thread is a tight twist & also because the stitching is constantly twisting or untwisting it as you stitch. Yes, you do have to let your needle dangle every now & again to let it twist back again. When you have completed the piece, give it a light press with a steam iron, face down on a fluffy towel with a dry cloth between the iron & the piece of work. This usually takes the 'spring' out of the work. Do you have it pinned onto a lace pillow whilst working it? This usually keeps it stable while you are stitching it too. Some threads have more twist in them than others plus your tension as well has a bearing on the end result. Hope this helps you.
My personal favorites as threads for needlelace are soft embroidery cottons such as DMC Broder cotton or Floche. At the present time DMC's broder cotton is only available in white and ecru, sizes 12/16/20/25. Sometimes you can find 30 and 50 by MEZ. The 12/16/10 are quite thick, comparable to Cordonnet 20. But they are a single strange, smooth and soft. DMC's Floche (size 14 I think) is now in colors. These are nice threads but are for people who like to work coarse, like me.
Sulky makes a nice 12/2 comparable to #12 pearl in beautiful colors. It is not as tightly twisted as crochet and tatting cottons and has a beautiful sheen. It still needs to unwind itself occasionally, but not as often as cordonnet.
Try threading your needle, and wusing the thread from the other end! this might unwind it slightly as you work, instead of overwinding as you work. you will still need to drop your needle occasionally, but perhaps not as much!
I was having trouble using some Brok, in a class with Catherine Barley, and she told me to try starting at the other end of the length of thread, - and it certainly helped.
I think that the only way the number of threads plied together matters is if the twisting of the threads is quite loose. Then when you are using the thread, the twists you put on it as you work are not so visible because the highly visible plies get in the way of seeing clearly. This is especially true of pearl 5 or pearl 8. When these are used in bobbin lace, it is hard to tell which twists are yours and which are the thread itself. So the thread detracts from all your efforts. The same may be true in needlelace. But if the number of plies is not highly visible I don't think it would matter. Different lacemakers have different preferences. I would only rrecommend that you try out many different threads on your various learning pieces to find threads that you like. Threads that are highly twisted seem to twist up more as you are working with them. Softer threads seem to twist up less. As far as I can see the number of plies is less a factor than how hard the twist.