I am also a hand quilter using a portable lap hoop. Right now I am working on a quilt that I am marking as I go. I have been using a marking pencil made by Sewline that uses ceramic lead. (I think that Fons and Porter has a similar one too.) It is a mechanical pencil with lead that comes in several colors. I really like it because the lines brush off like chalk but stays on a bit better than plain chalk. I also like it because I don't have to constantly sharpen it like I was when I used a marking pencil.