Heat gun works fine on yew.
Next time leave 1/4" of sapwood.
No sinew wrap.
My first several yew bows blew up. I mean literally. Biggest pieces less than a foot long. I still wince when I do the first long draw by hand. Not sure what I do differently now, but must have learned something from those explosions because now yew works fine for me.
Have fun and consider wearing a motorcycle helmet for the first few shots.