Hello, 
i am trying to make design library feature to create a hole that looks like this:

i will be used like this: 

i want to be able to change the gaps on beteen the red part en the green part with the hole. 
when i try to make this in a design library feature i struggle when i want to use it because solidworks always finds another solution than the one i intend. or i have the open each feature so it corrects itself.  
Does anyone got tips on how i can make this?