I am trying in making laminates of different thickness in SolidWorks surfacing but couldn't complete. Please see the attached model and images for exact coring. I request to have the exact model to the given requirement in surfacing and to understand how to model it. 

Note:

1) For reference am attaching .STEP format of base model as well. 

2) Creating one laminate core and doing linear pattern for other two. (time saving in modelling) 

Thanks in Advance