I have experience with the iS87 and also the S95 in GPSSS speedsurfing.
You ask whether the iS96 can handle a 7.2 racesail. Should be no problem.
I used a 7.4 racesail on my -smaller- iS87. No problem.
Of course iS87 is not a lightwind board, but for early planing you already have a bigger board. The Sonic95, which is the "father" of the iS94 and now iS96, is but also FEELS a bigger board. Sweetspot of this board is around 6.6-7.0 SqM. It is suitable for light-to-medium wind speedsurfing, but a bit too big for stronger winds.
In the 2007 range, the iS87 was the best board (in my opinion).
Not only very very fast (Martin van Meurs did 44 knots on 500 metres on this board). But also nice to jibe, and wide windrange. Planes up much earlier than you would expect from a board this size.
Be aware that the bigger iSonics (101 and up) have a different design. This makes them very good for long distance and slalom (average speed), but less good for speedsurfing (all-out topspeed).
What region of Germany do you live in?
If it's near to Holland, I know that Telstar in Harderwijk has got demo iS87 boards that you can test or rent.
Anyway, in your position you cannot go wrong with the iS87. Would recommend it over the iS96. My weight = 88 kgs, so just a little lighter than you.
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