Jason,
If you can still find one, a frontier arrow straightener works wonders on finished or unfinished ramin. I bought mine years ago when I shot a compound. They were origninally made for aluminum shafts, but they work just as well on wood. Especially ramin. Haven't seen one around in a long time though. I can even straighten a shaft with multiple bends.
the screwdriver trick does work well though. Much better than trying to straighten ramin with nothing but your hands.