I also remember Tim Baker stating that white oak regularly breaks AFTER hickory breaks. Maybe the compression strength is not as good as with hickory, but in tension it is supposedly great.
The thing is, with oaks (all oaks) is that there is considerable variation in density (less so with hickory). Some boards can have loads of earlywood, making the wood very brittle and weak. Other boards, often those with thicker rings, have nearly all latewood and thus a dramatically higher specific gravity. Eastman's board appears to have an above average amount of earlywood. It's not useless because of this, but it could well be that this board is a bit weaker than the average hickory. Since the board is perfectly square, you can easily do a test for determining the SG. Accurately measure the volume in cubic centimeters, and accurately record the weight (on a food scale or a bathroom scale). This will tell you the SG of the board and is a good indicator for strength.
What concerns me more, is that significant grain runoff in the third pic. In my opinion, this part would not be suitable for backing strips. Since you have the board already, you could cut the board in half; use the first half (from the first pic) for backing strips that will be seamed in the stiff handle of the bow. Use the second part, with the poor grain, as billets that will have to be backed. A splice or seam in the handle of the backing strips is not a problem, as long as the handle is stiff.
To get back to your question HOW to make backing strips...cut the board into long slats 2"x3/4"
Then turn it 90 degrees so the side of 3/4" wide touches the table of your circular saw (tablesaw). Then cut in half, which will create two strips of each about 1/4" thick. That is a bit too thick, I think, so you can plane/sand them to about 1/8" or 3/16".
