I use Crayola brand washable markers. They make a dark line and always wash out. I mark the whole quilt at once. When I used my big frame, I made the mistake of not basting first and ruined a quilt. So, be sure and baste very well. I also like the Clover marking tools in grey and white, and the water soluable pens. The purple pen fades too fast for me. I don't like the chalk, it rubs off faster than I can quilt. I don't use pencil because -even with a fabric eraser- I have had problems with it staying in.
Beautiful quilt, I bought fabric tonight that I think would look marvelous in that pattern. Is it one you can share?