@MaryKa totally agree with
@Gemm ... always important if making donation quilts to check before you make re any requirements.
If you go ahead with tying ... , you may want to consider using embroidery thread. Years ago when I took a Quilt-In-A-Day class, that's what we used. We did a double stitch in x-format for each tie, then tied it off with a tight pair of knots. With the embroidery thread the ties were almost invisible compared to a seemingly big wad that often results when using yarn!