I have an online friend who is a long armer (as well, I am one too), that uses serger thread and swears by it. I don't prefer it, but its a personal preference. I tend to stick with Permacore or Glide. I would hope that if you asked for something different, your long armer would honor your request. I don't quilt much for others, but I listen to what they ask for and offer my suggestions. If i had not used a certain thread before, I would be up front.