I'm trying to understand this post, yet I am failing. You're looking for a "template" for a frame that will be used for some undetermined type of riding (racing? touring? rando? runs to the store?) that is going to be a "custom" road frame that falls into a 3cm size range? It doesn't make a whole lot of sense. I would suggest starting in one of two ways: find a bike that DOES fit (or come close, where differences like a longer top tube can be extrapolated out), and take a series of very careful measurements; or, play around with BikeCAD for a little while.