I started doing mine today and I have a few tips already.
Our stitching is closer to a grey color so if you use the red FabricMate type dye pen it will look maroon not red.
I wasn't very happy when I started this morning so I went to walmart and picked up a Painters marker.
This is a acrylic paint filled marker. It makes the stitching much darker.
I also decided that I wasn't happy with the red color so I got a blue one.
It covered the FabricMate red without a problem.
I am soooooo glad that I went with the blue. It looks sick!
I am working on it now and I'll get some pics up a little later.