Great idea!
When you get your bow and the string finishes stretching/settling in mark the cams with a magic marker or better yet scribe a line that references with the string or the limb and that will tell you where to put the cams. It will also let you know before replacing the string if your cam timing is on or off. Don't forget to measure your tiller. On a crossbow I would assume they are eqaul but anyhow measure it and record the measurement for reference.
Dan, I wonder if a Bow Master Press would work?