The Arriba website lists the FX3 for the H16 but the older Hobie catalogs don't even show it; they only show the FX4 and FX6.
Maybe I'm answering my own question here; I'm not sure 8" extra is enough. I definitely run out of tiller when I am trapped low and when I'm solo at the front of the tramp.
On a related note there has been some sort of supply problem with the Hot Sticks. The Kitty Hawk dealer could not get them over the winter and at least some are still backordered. The company's website indicates that they have recently changed name and possibly ownership.
The Hobie catalog refers to an elastomeric end coupling while the Arriba site doesn't.
'00 H16 #104691 - '78 H16 #32692 ex-rental - Old Holsclaw trailerMy Hobie 16 pages