I have made 4 lgr quilts 2 king and 2 queens and a number of baby quilts, and tied with yarn, but my quilts were heavy quilts
made from used jeans, I tied with 6ply yarn that is what I had.
I made two twin and tied them also.
I tie mine about 4" a part. I like to do my tying stagered on the quilt. I also made different colored button from polamar clay to tie with. You can use old buttons also but it is alot if work on a lgr quilt.
Have fun and enjoy.