ANSWER
After working on it longer, I have determined "A" solution, not saying its the only solution, but it's working.
For my paging sizes, the requirements are 5, 10, or 20. The default is 5. So what I did is I created 3 data grids, I changed the page size via the properties on each data grid, one defaulted to 5, the other to 10, and the last one to 20.
I created a enumeration that has all three page sizes in it:
On the page that has the 3 data grids, I added a Variable called PageSize that is of type [THE ENUM I CREATED] and the default value set to 5:
Then for each data grid, under the visibility property, I added an expression that checks the variables value and sets true or false based on that variables value which would be 5, 10, or 20. Based on that, we will display the corresponding Data Grid showing that page size and hide the others.
The example below is the expression for the data grid that has a page size of 5
Hope this is able to help someone else wanting to do this very common thing. There probably is a better way to do it since this causes a maintainability issue with updating grids multiple time, but this is the way I solved the problem and it works.