RE: What wave board?
OK, the K96, sorry for my mix-up. That is indeed a bigger board and it will shift the range of use upwards in the sail size spectrum. In my experience, when you move away from a sort of "ideal all round size" of a board, the sail size spectrum not only shifts bat also decreases a bit, ie with a bigger board you loose more at the high wind end than you gain at the light wind end. Anyway, the 96 is still a valid choice and using a good deal to experiment a bit is definitely good since at the very least it will make you learn more about your own preferences.
Your despription of the fresh/salt water issue in the post above is more close to how I see it. I don't really think about the water quality, but is very observant of the wave/chop quality. Interestingly saom of the best wave spts in Sweden is in the Baltic ocean which is pretty much 100% fresh water. They still clearly get the best waves in Sweden, some fairly big monsters which can also continue to pump long after the wind dies. The Swedish west coast with its more salty water can get nice waves too, but they are more wind driven and pretty much go down the minute the wind dies. My conclusion is that these things have more to do with the coast line and water depth and such things than the actual water quality, but maybe the water quality has some influence too. I don't know how big the viscosity difference really is.
The 4-5m sweel in 9s periods actually reminds me of Guincho in Portugal (very salt water) which has a local wind phenomenon which can drive a medium swell up to these sizes sometimes. No easy sailing... Fortunately Guincho gets some real long period swell sometimes too (from distant storms).
Ray and Evan has some good points too and I agree that when you get big (great lake) waves (in high wind) an EVO will be the best board if you want to ride waves. Particularly that kind of low period "super big chop" is where the turning qualities of the EVO can shine. I would especially recomend the EVO 70 for such conditions (very good control) but the 75 is a nice choice too.
Evan: The A94 was a nice board, wasn't it? Both the new Kombats and Pure Acids have some of that heritage. Probably the K87 will sail the closest to the A94 (albeit with a bit less volume).