Thank you for thr input.
But I need the all dimensions, as I don't plan to order springs from France, and intend to buy here equivalent material, or to manufacture them by myself with appropriate caracteristics.
(I'm now flying, and after moving, I lost the Speedbreak addendum drawing years ago, and those I instal are too soft. I'll appreciate avoiding lot of flyght tests to reach approximatively the operative value........).
Regards