Dave, don't start out with too small a pot, they get big very fast! They'll absolutely grow to fit any pot you put them in.
My first two arrived as cuttings in spring of 2011 and I re-potted them 4 times by the end of the summer. (where's the icon for slapping oneself upside the head??)
Now, as I've said before, I just prune them back so I can keep them in the biggest pots I can handle, refresh the soil and root-prune in winter. They love to be pruned, and bloom better than ever since I stopped stressing and started doing this.
