As with most swordsmiths in the 16th century, I believe that Muramasa school was a workshop producing blades in small batches. The three generations always mentioned were the heads of the shop, but the actual craftsmen making the swords were more numerous. Blade length is approximately 25cm, the original is illustrated below.
This template is based on the historical blade and precision cut from 2.5mm mild steel. Note that the surface is unfinished and may show signs of oxidation and scale, some oiling and care is required occasionally.
Apprentices were asked to make as many kata as they could: these are eventually used for sword making, can be kept for a lifetime for reference and study, and their very making is a good opportunity for practice.
A good to way to learn proper sword sugata, or silhouette, is to make a kata, or pattern, from 1.25-1.5mm thick sheet of mild steel. Learn about making your own kata.