Me again--the guy who asked the original question. Sorry I forgot to leave a name, but it is John.
Okay, the first post suggested I try a Maui Sails Titan. I have a Maui Sails 2008 MS2 (the predecessor to the Titan) 7.5 meter and love it. It rigs easily, rotates easily, gives me good speeds, stays in control when super powered, and planes easily. As far as early planing is concerned, it is very good, much better than the Retro 7.5 I had before. In fact, one day last summer I was on that sail in wind I shouldn't have been planing in and I was flying back and forth, wondering what was going on to make me plane so early. But, the Maui Sail is not what Pryde claims the Helium is--something that provides the power of a sail a meter or two larger than it actually is. It is a darn good sail, but does not provide the equivalent power of a sail two meters larger. Soooo, I am still curious about the Pryde Helium.
Mark, thank you for referring me to those web sites. They explained a lot. The sites make the Helium sound as though there are some big tradeoffs: you get light wind planing from a smaller sail, but you lose top end control. The sites were useful to me in that regard. Where I live the wind can change from 12 to 45 in a matter of seconds, so I am thinking a sail with more twist off than the Helium might be better.
By the way, my 8.5 and 9.5 are Severne Elements. They seem like good sails and rig on a smallish boom because of the clew cut out, but they are not as powerful as Pryde claims the Helium to be. As I said, I live in a place where the wind can come up very suddenly, and one reason I was thinking of the Pryde Helium 8.5 was so that I could possibly get rid of my 9.5 and yet not losing any planing. The 9.5 is fun, but I got overpowered--down in the water overpowered--about six times last summer on it. So a smaller sail had some appeal.
So, what I am saying is that this information was helpful but I am still trying to figure out if the Helium 8.5 is right for me or not. If anyone has more info, please let me know by responding to this forum. I am leaning in the direction of saying the Helium is not for me.