Discrete Size Composite Optimization

Hello

I have to perform an optimization of a piece made of carbon fiber with a honeycomb core. Since I already have the material I will use for manufacturing, I don't want to optimize the ply thickness neither the size of the ply( I want the ply to have the same area as the surface it is assigned to).

This being said, what I want to know is what is the optimal shuffle order, the optimal orientation of the plies(0,90,45/-45) and the thickness of the core(which can vary from 5 to 25 mm).

What is the best approach to perform this? I have read and seen a lot of tutorials on how to perform composite optimization with Optiscruct, but they all start with Free-size optimization.

Thank you in advance