One can also check polars (although there do not appear to be many good sources) to get a rough idea of usable tacking angle and the tradeoff of pinching and VMG, etc. A few links/articles include:

http://www.hobiecat.com/forums/viewtopic.php?f=9&t=10337&start=0

Page 7 of the PDF here: http://www.hobieclass.com/site/hobie/ihca/downloads/hobieu/HobieU.pdf

and here (a theoretical comparison): http://www.thebeachcats.com/OnTheWire/westnet/_lpm/hobie/archives/v1-i3/feature3.htm