If i only used measures i wouldn't have any bows. All my bow wood is crooked, knotted, wavy and reflex or deflexed, which prevents me from using exact measures. Bow making is about learning to adjust. Sure you can make bows out of planks with measures, but i haven't been too interested in it. Only measures i take is the length and handle dimension. These two measures will basically tell you how heavy the bow is and lets you configure the stress. For example now that i found out 43x31mm handle will make a 155# pound and it doesn't take too much set, i could go for 41x33mm in the next bow. It should be little bit heavier (~170-190#?), but actually about the same in mass.