RE: I just ordered a Gemini!!
I'm the 'Phil' referred to in a previous post and thought I should pass on my experiences with the Gemini.
Set-up: There appears to be a large distance between the front track and the front set of straps and we set the deck plate at the back of the track to get comfortable - the photos in the link were taken before we moved the deck plates and you can see that Mike (on the front) doesn't look very comfortable despite having the boom at his usual height. The rear track is different and is closer to the rear set of straps. The best place we found for this deckplate was in the front 1/3 of the track.
The photos show a 7.5 on the back and 6.5 on the front.
Sailing: It's great fun! It planes pretty early but don't go for the straps until the board is planing freely as it does tend to head into wind quite easily, despite the straps being more inboard than you'd think. The rear straps (of the rear set) are in fact fixed to a cantilever behind the fin which I assume helps the manoverability.
Tacking is easy....if you've got Mike on the front who can helitack all day! Gybing is another matter that we haven't explored yet.....
Just remember to talk to each other, in between the laughter, and it's easy. Syncronised beach starting and landing looks pretty good - we haven't attempted syncronised water starts yet....
So far we've managed 26mph in pretty light winds and are looking to break 30 mph in the next few weeks.