Update:
I got my "check-go" device yesterday. I can't verify if it actually will help my game. I marked a ball, put it back in the machine (at a different angle) and the line returned to the correct position so it appears to be accurate so far.
Here are some pictures of it:
It's kind of small
With the ball in the cage ready to go
This picture was of the ball spinning as I marked it - but the picture looks different
the results
