I just started using rose shafts and i have found a couple of things. First, don't cut those with green colored bark. They seem to be young shoots that have a large pithy center. Red bark and the obviously old, gnarly-gray bark shafts are much, much stronger. Secondly, remove the outer layer of bark ASAP. There is an inner layer of bark that is very fibrous (which I believe would make decent cordage if peeled off green) that seems to keep the shaft from checking. I have seen the shafts split every which way with this layer removed too soon, but have not seen a split if this layer is left on. Thirdly, I have had good luck heating the shafts after only a day or so -- sometimes sooner. With the inner bark still on I heat an straighten while there is still quite a bit of moisture in the wood. Then everything seems to dry quickly with no (or very few) splits. I guess I just can't stand to wait a month or two.