Soap qualities (as they're called in Soap Calc) or Recipe Qualities (as they're called in Soap Making Friend) are determined mostly by the fats/oils used in a recipe. Additives, such as sugar or beer, modify those primary qualities, e.g. both sugar and beer help to create more/bigger bubbles. If you found a recipe that you like, you can make it at any lye concentration that works for you and your recipe. A higher lye concentration will produce a harder soap initially compared with a lower lye concentration, but that difference should evaporate away

as the soap cures. There are pros and cons to the use of various lye concentrations, which you may already have a feel for since you've made batter using lye concentrations ranging from 30% to 50%.