I've seen this done in the past by using fishing line, snapping a chalk line, and by laser. What is the best way to place a spot on new cloth? Thanks for any info you may offer... Mikey 
Snapping a chalk line? Lasers? These methods are overkill and unnecessary. If you think about what we're actually trying to accomplish here the best tools are a tape measure and a pencil! Never assume that the diamonds are perfectly aligned.
This has been said before but its worth repeating. First, measure the distance from the cushion nose from side to side. On an 8' table it should be 44", 9' should measure 50". Whatever the measurement is, just find the halfway point. Take that number and go up from the nose of the end cushion the same distance. For example, on a 9' table if the side to side distance is exactly 50", the center of the spot should be over 25" and up 25". Can't get any easier or more accurate than that!
Snapping a chalk line? Lasers? These methods are overkill and unnecessary. If you think about what we're actually trying to accomplish here the best tools are a tape measure and a pencil! Never assume that the diamonds are perfectly aligned.
This has been said before but its worth repeating. First, measure the distance from the cushion nose from side to side. On an 8' table it should be 44", 9' should measure 50". Whatever the measurement is, just find the halfway point. Take that number and go up from the nose of the end cushion the same distance. For example, on a 9' table if the side to side distance is exactly 50", the center of the spot should be over 25" and up 25". Can't get any easier or more accurate than that!
Bob,The diamonds should be aligned properly and the top should be squared. I have measured with tapes and used lasers. The difference if any is statistically incidental.
A laser in theory works as well as a tape. Playing surface size can vary along the same opposing rails. A tape can overlook curves in the rails unless measurement is taken in three places and the difference calculated. Rails can be concave or convex. I have installed new GC V's with a playing surface that is over 50 x !00. A tape works fine so does a laser. You could use each on any table and the variable would be so small it's not worth the time to debate or a good enough reason to discount someone's method. Does the use of a chalk line or laser automatically mean that the mechanic skipped squaring the top? That's an assumption not a matter of fact. I would endorse the use of a measuring tape to anyone. I would not suggest that a step in the process has to be skipped or overlooked to utilize your method.