Linking Sketch Dimensions to Seperate file

Hello everyone,

I am working on a project to speed up our tool design process for some products we offer.

Through lots of time and development I have made some equations that dictate how a material will form and behave for complex shapes in stamping.

What I would like to do is create a part and then link it to all of the tools using these equations. The problem is I want to edit a value in the final part (separate part file). and then when I go in to open the full die and such the values will link back to the part and change it.

I tried the following:

Creating a global variable in the actual file and tried to tie it to a dimension.-> So I placed a .5mm radius in a corner and I want to set the global variable as that value without typing it into the equation dialog. So if I go into the sketch and change it it updated the variable.

Then I want to go into the tool used to form that and say the corner radius of the tool should be 1/2 that of the parts. But I again do not want to have to type numbers in.

I am basically trying to automate the tool design process.

I have put some pictures below for reference....Does anyone have any links to help guide us on this.

for example the part is a .5mm radius. I want the separate file which is a separate  part to be a .25mm radius by an equation

SolidworksGeneral