With the hall width settings, the hall width is changed in the selected hall from the format settings section in the hall settings dialog.
Location of the Hall Width Setting
Select the hall you want to change the hall width and click the right mouse button. Click the Properties line from the right click menu that opens.
Enter the hall settings.
Enter the hall width value in the l1 box.
Your hall width will change to the values you entered.
Hall view before changing the hall width
Hall view after l1 is changed to 1500 cm
Hall view after l1 is changed to 3500 cm