Size doesn't matter on tying, I've tied as big as an oversized king. I personally prefer embroidery floss, some people use yarn, crochet thread, ribbon, etc. I personally like to tie approximately every 4", then I go in between the 4" and offset it 2", if that makes any sense to you, but this is just my own personal thing, I've seen tied quilts as far apart as 10" or maybe more.
As far as Joann's goes, it sometimes will take 3 or 4 months to get your fliers and e-mails notices started.