Thanks for the reply and the encourage.
I think that my calculations are correct, but I have done some bad calculations before so I'll never know you know[8D]
That calculation of the stall speed was just something I found on the web. (3.7 * SQRT(weight/wing area) (ft2 & oz)
You mention that 33% weight increase and then some is OK. My tucano is about 43% overweight.
For the first flights I will have a little over 2600 feet of runway, and the tucano has pneumatic wheelbrakes as well so I hope that I should get it to stop somewhere on that runway
I like it when my planes starts to descend when I reduce throttle and not when they are light and "ballooning" around., but I have never had a plane this far out on one side of the weight scale.