Yes, I missed that. I thought you were only talking about a single batten at the bottom edge as a workpiece support.
The open spaces in your design got me thinking this was possible as the space is required to place the clamps.
I like the idea of wings as a place to park the sled out of the way
- for changing the workpiece.
- so you can use the frame as a panel saw too.
- for easy access to the bottom of sled for changing bits.
The problem with wings is choosing the depth. If they are flush with the backside, they don’t do much. If they are flush with the frontside of the workpiece, what happens when your next workpiece is a different thickness?