craftgrrl | Working with dressmaker's carbon

I have this cross stitch kit that gets personalized. The way I am supposed to do it is put the letters on tracing paper, pin the blue carbon stuff to the canvas and place the tracing paper over that and trace over the x's in order to get them on the fabric.

I was looking for any tips for getting the best results. I don't want to mess this up as it will be a wedding present.. How light will the transfer be as I am putting these on for another person to sew. What's the best way , etc? I've never used the stuff before.

Crossposted all over