Just bought this piece of Osage on the Internet and I've never worked with Osage before.  The dimensions are: 2" x 72" x 3/4" thick. Please ... I need suggestions as to what I can do with it. It has a couple twists and turns in the grain and I hope the experts can give me tips on how to deal with those. Here are a few photos to illustrate what I'm talking about.
 
here's the first side
 
 
here's the second side
 
 

Oops ... having trouble posting pics ... let me try again.
   
here's the first side
   
   
and the other side
   
   

As long as you back it, it should be OK. I'd go with hickory backing but bamboo will work well also, maybe even hard maple or elm.

For a BBO longbow at 60# for 28"draw, which build would you recommend?

I'd go with hickory.

1 1/4" to 1 3/8" at the fades, out 8" with a straight taper to 1/2" tips. You can reduce the tips to 3/8" later. I'd go 64" to 66" for a 28" draw.
Hickory backing is a lot more simple to do, is a more reliable backing than boo and you'll hardly be able to tell the difference in performance if you do your part.

Yep, what pat said. Nice looking board

You are going to make an edge grain bow. From the grain swirl that shows in the board you may have some knots to deal with.

Look at the side of your board and see if there are any knots. You will need to position any knots in your cut out bow so they are up against your backing or in a position where they are removed  from the belly while tillering.

If you end up with any running crossways on your bows belly they will more then likely cause a bow failure.

Cut that spot at 10" off and you should be fine.  That will leave you with 62".  Get Dean Torges' Video "Hunting the Bamboo Backed Bow".  bowyersedge.com

For clarity, I would not call that a blank.  It is a slat, or a board.  A blank has the bow pretty much laid out and ready to start tillering.  At least in my mind.

Eric and John, you are both correct. Upon closer examination, it appears there is a knot running across right at the 10" mark. I guess I'll be making a 62" bow. Thanks for the advice.

That is a gorgeous blank for a Bamboo backed bow.  Get some madake bamboo from Jaap Keppendrayer and the video "Hunting the bamboo backed bow" from Dean torges.  Or you could just end it to me.....

I have had mixed results with Bamboo,like Pat said hickory backing may be more reliable.

Mark

It is all about the bamboo and how you treat the back during the finishing process.

I had really bad luck with slats from Frank's, very good luck from stuff I cut myself locally.

When I started leaving the nodes alone and did minimal scraping on the back I got out of failure mode.

I have built a lot of BBO bows and tri lam bows, but that board there would be cause for concern for me.

Why is that Roy? Is it because of the knot at the 10" mark? If I cut it off there, I have 62.5" remaining ... Isn't That enough for a bamboo backed longbow?

Also, would it help to slice the board into 2 separate laminations and flip and glue? Just a thought.

if you mean resaw that board into two lams, that might work. or you could cut in half and splice back together. I've done this many times to salvage a full length slat that had one or two pin knots in the wrong place, much like yours. I think I'd cut in half, or a couple inches in favor of the end with the knot. trim the end with the knot as much as you can and still maintain the desired length. Z-splice them back together with the knot end in the middle. ideally, with the 4" or so you lose to the splice plus whatever else you can afford to trim, the problem knot will wind up sandwiched between your backing and riser section and be of no further concern.