RE: low planing question :)
I just went down from a 2005 F-Type 158 to a 2006 F-Type 148, based on a desire to stay on it a bit longer as the wind and chop pick up, and based on input from Roger.
I do notice a very small loss on early planing in very marginal winds, but can stay on it a LOT longer as the wind and chop picks up. I used 8.5 and 9.5 Retros for both. I found the 158 felt best with the 9.5, but the 148 feels better with the 8.5. The 9.5 almost feels like it is pushing it for being a bit big for the 148, although the marketing sail range numbers say up to 10.5, so maybe I just haven't found the tuning sweet spot for that yet.
I was surprised they got rid of the 158 for 2007. For bigger guys, that is a sweet board. For me and what I was looking for, the 148 does the trick. But on REALLY light days I miss my 158 a little. But if you have to replace your 158 with an iSonic 155 down the road, you will probably be happy...
I am also considering getting the new Apollo for early planing on really light days, maybe with an 11.0, that looks like an interesting board, lowering the planing threshold by 2 knots is pretty amazing.