What is the exact siddur used at most Breslover kehillos? Does it vary? How about the one used at the Chut Shel Chessed Yeshiva in Jerusalem? I know it's probably Nusach Sefard, but which one?
Contacted Chut Shel Chessed Yeshiva and they said the most commonly used siddur they use is Siddur Tefillas Kol Peh. You can buy one here: http://www.greenfieldjudaica.com/siddur-tefillas-kol-peh-hardcover---hebrew-only-S104008.html Comes in Nusach Sefard or Ashkenaz, but keep in mind Breslovers usually daven Sefard unless they have a strong minhag of davening Nusach Ashkenaz.