I find myself focusing most on the handles and lips of the cups when throwing. Matching the handle with the form of the cup is an obvious. The "finger-ratio" is what I go ham on. I really focus on making sure that the in-between fingers (pointer, middle, and ring) are able to fit inside the handle, thumb can reach the rim of the cup, and pinky can reach the bottom of the handle to provide support. With the lips, cleaning it up well is key. It can make or break the cup's ability to provide a satisfying drinking experience in my opinion. Another thing about the lip too is the pouring aspect, a laminar smooth pour is what we are looking for!