My preference is towards 3/4" depth (overhang) and height on s&g kayaks, I think Rob is refereing to height above the deck, there are some british boats that are dangerously tight(shallow), a person could jam a finger and break it on some of them. For a flat piece of wood 1/2" overhang sounds narrow for some skirt combinations but the type of skirt probably is just as important. Just for the heck of it for the Merganser I'm finishing I glassed a 1" bias cut strip of 4oz all around the rounded edge of the 4mm ply,, for the amount of labor all of that entailed along with glassing on both sides (for a boat that would get used in instruction, many t-rescues) I wonder if making a glass coaming would have been just as easy.