Bringing moves to 100% is the reason every crafting class gets Steady Hand, and why Culinarian's 37 cross class move is Steady Hand 2.

That aside, you might want to invest in bringing Weaver up. Careful Synthesis is slightly less Efficiency than Basic Synthesis, but it is 100% success rate without any Steady Hand buff up.

For what its worth though - be glad that the RNG works the way it does. You would never get anything melded past the 2nd forced meld otherwise!