Since there is not a lot of info out there on the FX One I thought I would post some notes for reference:
We sail two-up, my GF and I weigh around 310-315 "without gear"
We can move her on cat trax with no problem, and we use a righting stick.
We our on our third season with the boat, we sail in saltwater in a sound, bay, as well as the ocean. Good prevailing winds!
We have little time on the spin, so nothing much to say other than you got a tiger by the tail when the wind is honking!
I have learned to get more power out of the main (mast rake is key) and do not really use the self tacker that much.
We have neutral mast rake (tried extreme - the boat looked like it was ready to sink) and lower angles on the spreaders.
I power up the main where a solo-sailor might need to de-power it, again, our mast rake and spreaders complement our crew weight and we have no problem flying the hull (with GF on the wire) in 10 knots.
The wave piercing hulls are mesmerizing to watch. Stuff them back to the front cross beam and keep on going.
Sometimes she tacks like a mono-hull, but I also perfected my big-air gybe for when she refuses to comply.
She is forgiving when you are flying the hull and a gust comes along, she doesn't hit hard like a big boat. You can really be smooth, almost stalling her in the wind with the hull up high - it's wild.
It seems the nastier the conditions turn the happier she is, she will run wide open through with water blowing through the tramp so hard you will go for a swim if you are not somehow tethered.
Great boat for new cat sailors concerned about pitch poles.
Great boat for experienced crews (up to 3 sails and 402 sft!)
Her sister (the Tiger) is similar yet there is a whole lot more to her than that 1' foot additional length.
All in all a great middleweight boat for those looking for something cutting edge and not just as a play-toy.