tutorials/Determine Line Number
To determine the correct line number for the stat you wish to modify you first need to look at the tooltip of the item.
The tooltip is split into lines, so even an empty line counts as 1 line. So the first line below the name starts at 1 and for each line you add 1. Below is an example of the line numbers.
To modify the Reflect stat I would type /ils lore 6.