Is it possible to obtain the sheet size (height and width of a sheet model) in order to use these in a constraint variable?

I'd like to develop a parametric drawing border cell that automatically changes size using 2D constraints and dimension constraints. I just started working with constraints and parametric cells. Is it perhaps necessary to first define item types that may use an EC Expression (perhaps something like "this.sheetDef() ??? ). Any suggestion is welcome including a perhaps totally different approach.