I'm very new here, and while my experience is limited here are some observations i have made. When i switched from a "cheap" brush (AOS Pure Badger) to a Good Brush (Silver Tip) my lather was more runny due to the extra water that the brush holds. Once i cut back on the water by shaking off as much as possible i was able to work up a much better lather with the good brush. I also travel alot and i have found that in each hotel i have to use a different amount of water which i would assume is due to how the water is treated R/O or filtered and ultimately how hard it is. I read somewhere that you can use glycerine in the soap to to make the lather more lubricative and i did try it and it did make a different but not a hugely noticeable one. In any event i think there is more art to working up a good lather than there is science, and the trick for me was adjusting only one variable at a time until i have found that "just right" combination that works for me. I don't fire on all cylinders every day, but now, more often than not I get the combination just right. I always err on the side of less water because i can always add more if i need to.