Since there's disagreement here sometimes on which is the maximum height from which LL makes sense, there is a study called "The height of choosiness: mutual mate choice for stature results in suboptimal pair formation for both sxxes" which as far as I know is one of the biggest studies conducted on height preferences for men and women. Among other things, it provides data on which heights benefit the most by gaining 2 inches, thus giving a quantitative answer to that question.
So the graph below shows a height, and by what percentage the dating pool of a man having that height would increase if he gained 2 inches. Keep in mind that those increases are relative, so for example that spike you see at 5'4 means that there is a very large difference between the dating pool of a 5'4 man and a 5'6 one, but the 5'6 man's is still small, it's just that the 5'4 man's is extremely small compared to the 5'6 man's. On the other hand, a 4'10 man's dating pool is so small that a 4'8 man doing 2-inch LL will see practically no benefits, even in relative terms.
Heights that have a multiplier of very close to or less than 1 (which starts around 5'11) are tall enough that gaining 2 inches would either give an extremely small change in acceptability to women, or even put them in the "too tall" range and reduce their dating pool. So for example that dip at 6'4 means a 6'4 man has a larger dating pool than a 6'6 man and doing LL would actually decrease his attractiveness. 5'11 being almost 1 means that there is very little difference in how acceptable 5'11 is to women compared to 6'1.
Up to you to interpret this graph based on your own situation, keeping in mind that it applies to US dating standards where average male height is 5'10 for young men (and the average height of the men who participated in the study was 5'10.5). Also, I converted the inches it was written with into feet'inches cause it's easier to interpret heights in that format. Based on it, the height range that benefits the most from LL is 5'4 to 5'6, and becomes pointless from 5'11 and below 5'0 (unless you add a very large amount of height).
I'm not a statistician, but I assume that if you want to see the benefits of doing more than 2 inches LL for any given pre-LL height you would have to add the percentage multipliers of multiple heights in a row. So for doing 4 inches LL at 5'4, you take the number for 5'4 (about 2.3) and add it to the one for 5'6 (about 2.2), giving an increase of 4.5 for going from 5'4 to 5'8, so 4.5 times more women will be OK with your height (correct me if I'm wrong).
