What exactly do you mean with horizontal space of the columns?
Do you mean the width of the columns?
You can set those with Table1.SetColumnsWidths.
In the demo program uncomment line 262 Table2.SetColumnsWidths(Array As Int(10dip... and you'll see the difference.
If it's the width of the line between columns, you can change the LineWidth property in the Designer.
But, in this case the lines between the rows will also be increased.
There is no horizontal scrollview, the table class is based on the ScrollView2D library.
The table scrolls horizontally automatically as soon as the total width of all columns is wider than the Table width.