If you don't plan on backing it I would go at least 68 for that draw length,1 1/2 TO 1 3/4 at the fads,tapered to the tip. I have made a few and they are nice and fast but they can also blow and when they do it is pretty violent. Some here have made some nice ones also,maybe they will chime in with some better ideas,I plan on sinewing the next one I do,I have seen some of them that were really nice.
I used only heart wood on mine,I think some have been leaving some or all the sap wood on the back like you would do with a yew stave.
That might be better because the ones I have had it is almost impossible to chase a ring for the back once you get to all heart wood.
Pappy