The Portrait Antiplanets are pretty rare and I have never seen one except on a collector's shelf (unused, sadly).
According Kingslake these were a modified version of the Petzval Portrait, but to me they look more like Petzval's Orthostigmat (another rare lens). From what I recall, they have a similar inward coma, so they should retain the sharp middle and fuzzy corners as the Petzval.
If you do buy the lens please post images! I would love to see what these lenses produce. If you don't buy it, please let me know who is selling it...