3. Change to VNAV and let the FMS calculate it all for you, arriving at point B exactly at FL220 and transitioning seamlessly to the next descent segment (if you dial down the altitude window).
With a properly set up CDU, I have not had any problems with RNAV arrivals done in VNAV. I don't know why others have so many problems.
FLCH and V/S are valuable when on vectors and when VNAV "falls behind" due to a shortened route. Use the proper mode for the situation.