Your question about marking -
If you use any type of pencil/fadeout/washout pen test it carefully on scraps from your quilt first. Some markers will "set" if exposed to heat/sunlight. Fabric marked with washout pens needs to be fully immersed in water to remove it, if you just spray or sponge, the marks can sink into the batting and come back up at a later date. Chalk pencils or chalk powder is usually safe as is a soap marker.