Set the depth of cut so that a full tooth of the blade extends below the workpiece. You'll be cutting right into the surface of the sacrificial table. The backbone of my system is a sacrificial cutting table with folding legs. Picture that unwieldy sheet of plywood lying serenely on a dedicated cutting table, waiting to be operated on like a patient in surgery. When each cut has been completed, both halves of the sheet will still be lying there, awaiting further disposition.
Nothing caves in or falls off the end.
The table is cheap, easy to build and lightweight, and you can store it in a narrow space when you're not using it. It doesn't take a 4-ft. I build mine a little under 3 ft. by 7 ft. This size is comfortable to work on and easy to store. If you have to cut a foot or less off one end of the sheet, you can slide it over so that the far end hangs over a foot or two.