Quote Originally Posted by Green_and_a_Half View Post
dont do anything buy careful from the beginning except master meld and piece by piece. should go unstable at 70% progress
i have 100 crafting 140control and 90 magcraft roughly.
It depends on both craftsmanship and control really. If you want instability, you want them as low enough such that you get one stability per synth but not twice.

Craftsmanship low = more failures = more chances of instability
Control low = high chance of instability per fail

As for how much exactly, that's anyone's guess and it would vary with recipe.