Resize GridPanel Columns UMG

Hi,

In my game, my UI will have a bar with 3 sections. These sections will resize as time goes on to represent certain game states, and each one can become bigger or smaller - the bar always remains the same total length. My approach thus far was to have a GridPanel with 3 columns. My sections can then be changed in size simply by editing the “Column Fill” properties for each Column.

The problem is that I cannot seem to figure out how to do this at runtime, or how to bind these fill properties to a specific series of gameplay variables that I have.

Is this the correct approach to take? If so, what is the method by which I can change the column fill at runtime? If not, is there a more appropriate control?

Thanks!