How to change the column width/ratio in Flexible Column Layout?

I wanted to have a 50%/50% ratio, but it seems not possible according to Documentation

Although the FlexibleColumnLayout can display 2 or 3 pages at one time, they can never have equal width (50%/50% or 33%/33%/33%). One of the pages is always larger (expanded) or even takes up the full width of the control (fullscreen). This is intentional because users should have a clear indication of what to focus their attention on at any given moment, for example, a list of items, one particular item, one item’s details.

Now I'm using sap.ui.layout.ResponsiveSplitter instead.