Thanks Eric, I do really appreciate your input. Although there is nothing in me that wants much at all to do with 9.5's. I'm far more likely (very likely at this stage) to size down from the 8.4 back to a 7.5 as my everyday sail, and to have a little 6.3 soft sail for flipping around when I'm in the mood.
One mast, one boom, one extension, one board, one cammed sail and one soft sail, either of which can be used in all weather. (Well most anyhow....) Sounds like minimalist windsurfing gear heaven to me.
Was sailing earlier today in 18 gusting 25 with the 8.4 on the Lechner. I can do it and all, but I'm sure as sure can be that I would have had more fun with a bit less sail. Should have gone with a 7.5 in the first place, I was too influenced by all the 9.5's around.
I do take on board though that I'm probably better just getting a 7.5 version of what I have already than getting all experimental with inspiration from the past....