I build mostly osage bows, and mostly in the low to mid 60s at the same 25" draw.  I prefer 60-62" lengths for rigid handled bows that are 1-3/8" t 1-1/2" wide.  For your stave's length, I (at least) would make an unbacked working handled bow.  Depending on stave quality and my mood, 1-1/4" to 1-3/8" wide for 60-ish weights, and about a quarter inch less for 50's and same reduction for 40's.  I also prefer radiused bellies unless I'm making a sapling bow with a VERY high crown.