Now that you've rotated the text, you could resize the rows and columns to make better use of the horizontal space you have gained. One way to do this is to use the optimal row height and optimal column width features.

Let's optimize the column widths first. Make sure the four rotated columns are selected, then right click on the column heading. Select the optimal column width command.

By default OpenOffice will add a bit of space the width to make things more readable. Click the OK button and the columns be resized to be just a bit larger that the longest column value.

A quicker way to set a row or column to optimal size is to double click on the divider line to the right of the column. Or click on the line divider just below the row you want to optimize.

You can manually adjust the size of a cell by clicking on the divider line between cells and dragging the mouse until the cell is the size you want.