My 1960 Caddy had a two-piece (factory) and it was necessary...but that car was an all-stock restoration and had a lot of suspension travel...If you are setting your car to ride low and with not a lot of travel, you may be able to get away with a one piece...
You could pretty easily make a mock-up driveshaft (plastic pipe, etc) to check it out and see what your angles are, X-Frame center section tunnel interference, etc at min/max ride height.
