Either use water:lye ratios as Seven does or use NaOH solution concentration in percent. Both are measuring what you really need to know -- the lye concentration. I don't know where the lye as % of oils comes from, but it's not particularly useful information, so I don't use it in my soap making.
1:1 water:lye ratio is a 50% NaOH solution. Tricky to get the NaOH fully dissolved, so I do not recommend this for beginners.
1.5:1 water:lye ratio is a 40% NaOH solution. This is a less common "lye discount".
2:1 water:lye ratio is a 33% NaOH solution. This is probably the most common "lye discount". I normally use this solution concentration.
2.5:1 water:lye ratio is a 28-29% NaOH solution Basically, this is "full water" and roughly translates to 38% NaOH as % of oils.
3:1 water:lye ratio is a 25% NaOH solution. Some use a lye solution this dilute when making HP soap. If used for CP soap, this much water can prevent the soap batter from forming a stable emulsion, so the soap can separate out after being poured in the mold.
More concentrated lye solutions (33% and higher) do NOT shorten the cure time, regardless of the "common wisdom" that says it does. It takes time for water to migrate from the center of the soap to the outside surface where it can actually evaporate. That process is slow, regardless of what lye concentration you used to make the soap. There are several informal studies from the last year or so that are floating around on SMF. They show the rate of weight loss from "full water" soaps and "water discount" soaps is about the same.
A more concentrated lye solution does tend to reduce the time to trace, and that is helpful with a recipe that is mostly or all liquid oils. It also will tend to make a harder soap at the time of unmolding, again helpful with a recipe that is mostly or all liquid oils. Using a "water discount" is not any more dangerous or risky than using a "full water" lye concentration. I don't get this bit of "common wisdom" either.