Oregon Mouse
If we haven't managed to put you off and you are still reading this...
I have been doing some more thinking about your "ideal" shelter. I cannot come up with any other lighter/better solution than to pick one of your three choices. The Refuge and the O2 have great space for weight ratio but I would only use them in fairly sheltered areas, the Refuge X (the Cuben version) is lighter again but not only has a less than ideal aerodynamic shape but also Cuben is proving to have very little puncture resistance and therefore prone to fail where it is stitched.
Spinnaker is often commented upon as beign noisy, note though that once it is up and set up correctly it does not flap and therefore there is no more noise to be heard. I have only seen one negative comment about spinnaker (not cost related) and that was from Ryan Jordan : The problem with Spinnaker's no-stretch gig is that when it fails, it fails catastophically. It is drastically weaker than silnylon.

When I was prototyping Stealth (LITE) Tarps, I blew out two in one weekend of high winds in the Tetons. Those were near-seam failures that were subsequently "managed" by better seams, but the reality is that the fabric explodes when it does go!

All of the GG designs deal with Spinnaker fabric well enough that this won't be an issue if you are camping in mild weather, but if you are in high winds, it should be something hanging out in the back of your mind <img src="/forums/images/graemlins/smile.gif" alt="" /> That was the impetus behind making a "PRO" version of the Stealth tarps, that fabric is really strong and we've never had a fabric failure on those.
don't think I'd worry about it in the Squall Classic, which is designed for thru-hiking the AT or PCT during the summer.
I know a guy that has a lot of experience with the type of shelters you are after including the Squall Classic, so I will ask his opinion and let you know if you are still interested. He is away at the moment.
Gossamer Gear now have a new batch of spinnaker but they will ship only in the new year, so you have some time to think about this....

Franco