The Frixion pens that we use have a nib of 0.5 not the 0.7 that you find in the supermarket. This finer nib is ideal for marking Sashiko, quilting or embroidery designs. We have black or blue coloured pens.
As a Frixion pen marks are removed by heat, it can be removed by running the iron over it, just remember, you must live with any creases until you have finished stitching!
You should try it on a small sample of the fabric before using it extensively, especially on batik fabrics.