I draw the bow and have my wife snap a pic. I use a calibrated arrow to know my draw length and a scale for weight. There is a thin line center of my phone screen my wife uses to line up exactly with the arrow for perfe t photos every time. The I use the edges of my phone screen to line the tips up on. If one bend more than the other, one limb tip will touch my screen edge before the other. I thinking about making a laminated grip on my phone screen to remove when not in use. Then when looking at other peoples tillers I can judge it very well with a grid if I wanted too.