Issues sizing scroll box children

Hi All,

I’m having trouble sizing the children in my scroll box. Im adding a widget into the scroll box in editor and runtime and i can’t see how i can set the width to what i want. Attatched is a shot of the widget im adding, the blueprints for creating and the results in editor and at runtime.

When i run the code at runtime the children get stretched but in editor its really skinny. Im pretty new to Unreal but i can’t see any settings to set the width other than the alignment which i’ve got to stretch the vertical to match the scroll box height.