How to apply shell to a solid body that has variable fillet on it

[designBXFKW]

I have a solid body that has varaible fillet on two sides and I want  to apply outside shell on it.  Because of the varaible fillets fusion cannot execute this procedure. The message it appears is :"Error: The operation could not create a valid result. Try adjusting the values or changing the inputs. " Can anyone help?

[TrippyLighting]

Please share the model.(export as .f3d and attach to a post.
I can already tell you that in its current form this is very unlikely to shell ever. The problem with the fillet is not that it is variable, but that is ends in a point.