Hi, 

As mentioned, the only way to set the header height to a specific pixel value is to use RowLayouts. To achieve that, you would do something like this: 

        private void ultraGrid1_InitializeLayout(object sender, Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs e)
        {
            var layout = e.Layout;
            var band = layout.Bands[0];
            var ov = layout.Override;

            band.RowLayoutStyle = RowLayoutStyle.ColumnLayout;
            // Assuming that none of the other columns PreferredLabelSize is set
            // you can simply set the height of one of them to affect all headers
            // in the band. 
            band.Columns[0].RowLayoutColumnInfo.PreferredLabelSize = new Size(0, 100);
        }

This might be a good solution for you, but you should be aware that using RowLayouts will carry with it certain changes to how the grid looks (you might notice a different in spacing or padding of cells) And also and certain limitations - using RowLayots this will disable Fixed (column) Headers, as fixed headers and RowLayouts are mutually exclusive. If you are not using Fixed Headers, anyway, then this is probably a good way to go.