The 12.5 Ion3 turns quicker than the Ion2 Version and flies a little bit quicker through the air... a bit more bite, I suppose
What I've noticed most on the Ion3s is the bar pressure is spot on... not too light that you don't get any feedback and not too heavy that you get tennis elbow. It feels really nicely balanced in that sense.
Flexi R&D works very much on a refinement process and resists change for change's sake. I guess it's important to keep producing new kites every year but it's also important to continuously refine a design that works well. The Ion3s a refined version of an already great kite.
The Ion3 bridle is different... it supports more of the kite in the center and less at the tips which helps with the turning characteristics. (Don't ask me if you can put an Ion3 bridle on an Ion2 tho... I don't know! Possibly not!)
Since you're 95Kg, I reckon the Ion3 12.5 would be good for you. I'd guess at 15knots it'll start to be fun and after 30 it'll start to get full on! But it varies so much from rider to rider, I really don't like guessing at what'll work for you without having seen you ride.
The 10.5 Ion2 is a sweet kite... A lot of people I ride with use it and get on really well with it either overpowered or as a light wind alternative with a skimboard. I would say the 12.5 will be better for you with the skim, just because it's bigger, but being nice and responsive, you can still get that bit extra by working the 12.5 in light winds.
As a heavier rider, I'd definitely recommend making use of the rearmost attachment points for the front lines... the heavier you are, the easier it is to edge the kite to the front of the window, Moving the front attachment points back gives you less depower, but the kite sits a bit further back in the window when it flies and will power heavier riders along, no worries. It also works well for freestyle having the extra grunt for more pop. This only seems to work down to a certain wind speed (lower for lighter riders) when you can get more power from apparent wind from a faster flying kite, so time for the front attachments.
I would have to say go for the 12.5 and save up for the 8.5 for your high wind kite. Master the skimboard on days when there's not quite enough for the 12.5 on your twin tip. If you go 10.5 then you might still want a smaller kite for when it's howling but need a bigger one on the skimboard.
You must have had an early session!
How heavy are you? 40mph and I'd be getting pretty high on a 6mIon2. I'd have to see you ride to tell if it was you or the kite doing something wrong. From where I'm standing, it could be either
The 6m turns fast and it's easy to over send the kite and do swingy pendulum jumps. Don't send it hard enough and you miss the most boost. On small kites, it's also easy to have the kite pull too hard coz they power up quicker - quicker than you can jump sometimes... if you don't jump with your legs hard enough, the kite will deform more under a higher load. and you'll get less boost. For me, the 6m was more of a fun high wind kite whereas a 7 gets that little bit more serious