I always taper mine from about 1/8" in the center to about 1/16" at the tips. After I flatten my boo with the jointer, I cut it to width ( a little from each side to keep the crown centered ), then I take a blow torch to it to drive out any moisture. A heat gun will work, but a propane torch will give too much heat. You don't have to darken it, just heat it some to dry it. You will see it begin to curve up towards the back and the flat you just planed will become curved the opposite of how it was before. Now you can plane it some more and it will thin down nicely and be flatter in profile. After this, I cut it to shape and give it it's taper. Plane or sand from the tip in about a foot, then again to about 2 feet, do the other end the same and then give it one more pass full length.
If you do use a jointer, make sure you take really light cuts or the cutter could blow up the thin bamboo. I push it through using two push pads, always maintaining downward pressure with one while bringing the other around to begin pushing again right behind the first.
Dave.