A mate is very happy with the H&B centrestand on his III.
I'm not a fan of top cases - they may be convenient for commuting, but they are oh so ugly, and seem to have a tendency to fall off unexpectedly. I'm happier with a soft or semi-rigid bag on the rear rack - the OEM one is very solid & has better lines than the H&B version.
Enjoy the new acquisition - lots of fun there.
