I've had some experience with my UPS now and can report that I really like it and it adds a lot of speed and fun. It comes into its' own from footing a beat through close and beam reaching and up to a broad reach, but after 135 degrees it wallows around like a genoa, maybe lowering the main would keep it filled. If you had an articulating sprit/pole that could be moved to weather it would probably do great, or you can wing and wing it. I have been constantly impressed by the speeds attained in light air, like 4kn in 5kn of wind!
I had some problems with how I installed it: I use a Harken furler out on a sprit about 18 inches forward of the forestay, and the spinnaker halyard block was about a foot higher than the forestay tang. I had problems when furling (I furl when tacking) the sail would get wrapped up around the forestay (I don't set the jib on the forestay, its' on a furler a few inches aft of the forestay- the forestay is used only to pull the mast up/down and set the mast rake). So, I moved the spinnaker block almost up to the masthead, which should separate the furled spinnaker (UPS) from the forestay, we'll see next sail... Also, the harken furler specs a 3/16" line but the UPS has a 9 foot foot and the 3/16 line fills the spool and jams. I replaced it with 9/64" line but that was able to 'fall thru' the bottom of the furler and jam when under high load. Guess i'll have to try 4mm line.