I have not made a successful bow nor have I ever used yew.
Hate to be the Stick In The Mud.... but here goes...
What I have done in a similar situation is to study my Yew Staves while doing some deep searches and such on the topic.
At the same time building bows from other more easily obtainable woods.
There by building a successful knowledge base to launch into More challenging woods and designs.
Better to learn on a Nice piece of Elm, HHB or Oak.
Saving that Fine piece of Yew till you get a couple of working bows under your belt.
Just my two cents...
-gus