Off-camera flash with a pocketwizard lets you use your flash in several positions with a minimal requirement of power supplies and the availability of quick lighting changes.
The old IR system caused several issues in bright light, radio control works very well. ETTL tends to get a little confused from time to time but during events compensating it should work if the circumstances are not too tricky. For portrait sessions you want the light to be consistent so just put the flash on manual.
Put the flash on manual (1/4 power used here), adjust ISO , shutter speed and the aperture in manual mode and voilà, a few quick shots in the courtyard with one hot shoe flash on a light stand via pocketwizard triggers. Used an omnibounce on the flash for some diffusion too.
Hereunder I put the flash behind the subject at approx. 45 degrees.