Only 2 possible solutions: 1. Recode either Tinkering or Assassination to give you the recipe for Sneaky Assassin's C'bow at a certain level. OR 2. Make Sneaky Assassin's C'bow NOT a Hidden Recipe. I Usually prefer the Wind Up Doubleplus or even the Cranky Crossbow over the Sneaky Assassin's. It's Piercing Damage is just too low to be worth it.