Head sails have changed since when I first crewed on a race tuned San Juan 24 back in the 70's when a spinnaker could only be used as a down wind sail with very little leeway towards a reach. That included having to haul a spinnaker pole off deck, attach the uphaul and downhaul lines, making sure that you didn't snag the whole mess on a jibe...
Whatever, that was then this is now.
Sometimes after that some bright mind invented the Gennaker. It did away with the pole by attaching a bridle to the Roller furled Jib with a simple down haul line to keep it from riding up on the jib, and re cutting the symetrical chute to combine a Spinnaker with a Genoa.
When I first installed a used Spinnaker on my '84 US built Catalina 27, it was useless without a pole. (My previous bare boat charter clients dropped the pole into the drink). I took the sail to the fine people at North Sails in Richmond, BC who recut it as a Gennaker complete with the needed hardware.
The first time I launched it, I was in Bliss, as my boat took off like a rocket in a 15 knot breeze. However it didn't take me long for me to figure out that on anything close to a reach this sail sucked (and became down right dangerous).
I took it back to North Sails and asked them to flatten it. They did a superb job on it and it allowed an almost true reach.
So what does this have to do with the Spinnaker on a Wave?
Well instead of calling it a 'Spinnaker', I think a Gennaker might be the right name for it.
The standard spinnaker sold by Hobie is an Asymmetrical Spinnaker. It has been noted on other sites that this basic sail can be recut flatter and allow a far better latitude to allow the user almost 180 degrees of usage at the expense of down wind ability. Considering that a Cat has problems when going directly downwind, I would consider a flattened chute as a huge bonus in performance simply by sailing off the usual downwind wing on wing arrangement.
If that is the intended use, I strongly recommend that cam cleats are installed for the sheet(s) to take the weight off.
There is also one fact that you cannot dismiss if you are thinking of a larger Chute for the Wave: The difference between the Shroud tang and the Spinnaker tang is 20 inches. Think strongly before you drill into the composite part of the mast as this is the last place where you would want to leave holes. However adding another, higher tang could also be a possibility down the line to use the lower for higher winds and the higher one for light airs (but will need an extra line...etc. etc. A larger kite will also probably need a lengthened pole with built in pre-stress and modified pole rigging...
...this is where I believe Jack Woehrle should take over on this conversation as he has far more experience in this matter than myself because he has taken this small boat way above the norm with amazing results.
Your opinions are sincerely welcomed.