Hi Alvaro Corral,
Thanks for contacting Syncfusion support.
It is possible to adjust the column width and space between the segments using Width and Spacing properties of ColumnSeries. The default value of Width is 0.8 and Spacing is 0.2.
Code Example [C#]:
ColumnSeries series1 = new ColumnSeries();
series1.Width = 0.2;
series1.Spacing = 0.7;
ColumnSeries series2 = new ColumnSeries();
series2.Width = 0.2;
series2.Spacing = 0.7;