For me, and this is just my opinion, I wouldnt use the twine to tie her up. I understand its so it will break if she sets back, but, IMHO that would only set up her for more pulling back. Once she does it and learns she can break free, she will do it more and more, btdt and took me 4 years to get my mare over it. That is a great idea for attaching a halter if it needs to be left on in pasture though.
If you are trying to cure a pullback or tieing problem, again, imho, the best thing is to use items that will not break, BUT, have great give in them. If you tie to an inner tube it will give, quite a bit, which will alleviate some of the fear from pulling back. Or if you use a tie ring ( its a free swinging ring with a 'finger' sticking up, you runt he lead behind the finger which gives tension and allows the lead to run out) and a good 20-30' of rope, she will also learn that if she sets back, she cannot get loose, but she can have that fear release. Generally, it only takes a few times for a horse ( that wasnt traumatized badly) to learn that they cant get hurt nor get loose if they pull back.
If you are trying to cure a pullback or tieing problem, again, imho, the best thing is to use items that will not break, BUT, have great give in them. If you tie to an inner tube it will give, quite a bit, which will alleviate some of the fear from pulling back. Or if you use a tie ring ( its a free swinging ring with a 'finger' sticking up, you runt he lead behind the finger which gives tension and allows the lead to run out) and a good 20-30' of rope, she will also learn that if she sets back, she cannot get loose, but she can have that fear release. Generally, it only takes a few times for a horse ( that wasnt traumatized badly) to learn that they cant get hurt nor get loose if they pull back.
