If you're going to use a temporary string along with your long string then be aware that your bow's tiller profile will change when you go to a short string. Using the long string you want to see the bow's greater bend near the handle and progressively stiffer to the tips. Then when you go to the short string you'll see the tiller shift with less bend near the handle and the greater bend move out towards the tip.
If you think about it, if you're at the point to where you can use this temporary method, then why not go ahead and string up your bow to get a true picture of your tiller...…….Art