Basically we are looking at a 2:6 ratio of 80 proof alcohol to non-alcoholic ingredients. I worked with these machines a lifetime ago with off the shelf mixes (Copeland's of New Orleans) and now in SF we are making fresh ingredient versions and having a blast. I find the most important things to keep straight (in addition to sugar) is know the proof of the alcohol you are using and making the batches easy to follow for the "next guy." As Mitchell says..go METRIC... In this case 2L Rum + 1L Lime + 1L Simple + 4L Water will yield you an 8L batch. Easy to mix/store/fill in a large cambro and more or less "fool proof" for your Monday Bartender. Simple syrup - 1 : 1 ratio water to sugar heated to disolve and cooled.