The largest number on the horizontal axis, in the run length plot. Or, the largest value of t on the plot for which P(RL=t) is plotted. For example, selecting 500 will give a probability plot of run-lengths in the range 1,2,...,500.
Quality isn't something that can be argued into an article or promised into it. It must be put there. If it isn't put there, the finest sales talk in the world won't act as a substitute.