yarn or crochet or cotton, I have never used floss. Some of my best memories are tying quilts.

I prefer the pearl cotton. It is easy to tie and doesn't fray. congrats on the quilt, sounds lovely

#3 Perle Cotton would work best. I love the ribbon idea. I have a red, white, and blue top my Mother made of poly knit material. I'm going to tie it and may try the ribbon. Wonder if I could find a red, white, blue ribbon???

I think I use Perle Cotton--is that the crochet thread? That's what I use. It comes in lots of colors. I've used it for decades, and it really holds up.

I've used embroidery floss, square knots, and left the ties about an inch long. After repeated washings the knots untied and the floss came out.

If you use ribbon... the cut edges will shred, so you'd have to use fray-check or something similar.

Am I right in thinking that later if I want too, I could snip out the ties and machine quilt the project?

I use fine crochet cotton. I can usually get partially used up balls at the thrift shop in all kinds of colors. It is great for that Japanese style of quilting with big stitches to make a pattern, I can't spell the name but it sounds like "shashico". I also put a dot of fabric glue on each knot to keep it strong.

Thanks for asking this question, I was wondering too what to use.

What is a 'tied' quilt?

Google- images- "Hand tying a quilt". It's just what it says, tying little knots at various intervals instead of "quilting" the top. Many great pictures there!