I think you will have to use the Optimization/Feasibility menu:
You will have to settle on more geometric items for the Design Variables such as thickness, height, etc.
Add them to the Design Variables list with a range of Min & Max.
Then complete a Mechanica Analysis.
You will have to decide what is your Design Goal because you can only pick one I believe:
Von Mises Stress of the bow.
I have used this before and it is very effective. Except Mechanica cannot auto converge the elements like Ansys can so you will then have to run your results 3 times with smaller and smaller mesh until the results are consistent.