If you can locate the video by Don Iovino, you will learn more than you need to know about those old paper graphs. He has probably spent more time looking at an old lowrance paper graph screen than anyone else around. The tape has all the details to get it dialed in. Try your local tackle store and see if they can inquire as to if he still has some available. He sells out of his garage so they should be able to order one for you if its available.
Good luck, there are very few units that give as good of a picture as the old X-16's.