viewports being set after both onBefore and onReady have executed

So , what I was hoping is that when the window opens and page is loaded, the order should be as below:
1)setting up of viewport
2)execution of onBefore
3)execution of onReady
4)capturing of snapshots

But right now what happens is:
1)execution of onBefore
2)execution of onReady
3 setting up of viewport
4)capturing of snapshots
The issue with this is that in my onReady script I am performing some steps which brings up a popup, now when the setting up of viewport happens after that popup is already there, the pop gets misaligned. When I am doing the same steps manually by first setting up viewport and then performing steps to bring that popup , it shows up in correct place.
Is there a way the viewport is set at the very beginning and then the onBefore/ready scripts are run?