...(Sedu, Solia, HAI or CHI?)? My hair is naturally relaxed, fine, and long. Which iron will work best, and be less damaging for my hair type? (Sedu, Solia, HAI or CHI?)

even though my hair is probably like the opposite of yours (it's curly, thick, and natural) I use the sedu and it works really good and my mom uses it on her hair sometimes (her hair is relaxed straight) and it also works really well for her too. So I recommend it without a doubt and I also recommend getting the wider one that they offer so it won't take as long to do your hair.