Unlike that other extension no need to wonder how much room, just thinking about setting and removing without tool. In fact dimensions was led by the cast iron table and size between the saw table and the workbench. As shown in the below drawing the extension receives the workpiece out of the saw table which is its main use or works as an infeed table with planer and most of time hangs along the wall when no need.

No doubt about dimensions. The extension couldn't exceed table saw width minus the sliding carriage and length was defined so that it could lock automatically when setting.

Regarding table saw the extension sits on two carriage bolts with enough room left between the head bolt and the table so that the aluminium angle could freely slide. Size between planer table holes didn't match with saw table. As a consequence a metal plate was clamped underneath reserving space for the aluminium fitting.

The other side holds a rebated wood stock and lock the extension when setting at the rear of the saw table. Using the roller stand is probably the best way of adjusting the extension flush with the planer table although lining up is not very convenient.

The stratified top came from an old kitchen furniture and the structure from a waste oak. Top and structure were stuck without any fastener. An aluminium angle 50x30x2mm screwed in a rabbet joint the extension flush with the cast iron table whereas the rebated piece of wood wedge the extension at the other end.