straight osage not necessary,,if you set out to find straight osage you will go blind and crazy,,
the only thing that matters is that you have quality wood,, by that i mean the earlywood to late wood ratio is good,,nothing else matters,,you can make it straight,, but you can not make bad wood good. I passed up a hundred trees yesterday that were dead straight and would have split out perfectly straight staves but the earlywood latewood ratio was bad making the wood useless,, If you cant tell by looking at the tree , take a small wedge of wood off the tree next to ground level,,you can look at the rings without cutting the tree ,,and remember the rings get smaller and worse as you go up the tree,,so if they are bad and the stump at 6ft they will be real bad,,