Wirelessly posted (BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

You do not have to book by March 31 to get the bonus; you merely have to transfer the MR points by March 31 to get the bonus. Whether you want to transfer the points now, without knowing whether you will ultimately be able to get the redemption you want, is another matter.

I think you're looking at the wrong redemption chart: I believe a redemption on CX from the U.S. to the Far East is only 25K or 30K BA miles each way in Coach. Make sure that you're looking at the "single partner (not BA)" redemption chart.

And yes, you would have to call BA to book, because you want the free stopover in HKG.