The problem is you still really haven't asked a question. It's a long paragraph that doesn't really tell anyone anything about what you are trying to accomplish... control algorithms.? Are you making a gyro system.. there isn't going to be a magical control algorithm to make a plane hover on it's own.. if you want that put a couple gyros in it or something.

1kg in equipment is a lot of weight... 2.2 pounds in a 70" plane can easily be make or break for 3D.. and will dramactically effect a 90" wingspan plane. The larger the better. How this plane 3Ds empty verses adding 2.2 pounds to it will be a night and day difference. You want a plane with the most square inches on the wings... I would be looking at something like an Extremeflight 88" Yak with 1450 sq inches it will take the extra weight a bit better.

At any rate I hope you have a pilot who can fly incolved in the project. Its one thing to fly around on a sim.. its another to actually do it and have a few grand in the air that you have to land saftly again