I NEVER try tillering Osage less than a year old,I prefer 2 or 3 or more. I do rough them out sometime while green seal, steam and straighten ,then date and put up for as long as I can
stand it.Also never use dry heat on Green Osage,any wood for that matter,it will check bad
if you do.
You may be in a hurry but I can almost promise you if you try it green you won't be happy with the outcome.
Most white wood you can work faster,I have done Hickory or
HHB in a little over a month from tree to bow just buy working it down a little at a time and
letting it dry over an AC duct or heat box in between working on it.
Pappy