Nothing special here, except that you can see I glued some rubber pads to the feet to protect the deck and help keep the stool from sliding around. I also added a strip of rubber under the seat where it sits on the edge of the companionway opening. I made the seat solid because I stand on it to raise the mast. This has proved to be a huge help, placing me a bit further forward and about 6" higher.
In the below shot from inside the cabin you can see the steps. The lowest step also serves as a foot rest, and the steps make it a bit more convenient to climb in and out of the cabin:
I made the "ladder" a bit steep for added strength since I will be standing on the stool to raise the mast. You can probably see that the cutout for the CB trunk is a bit off-center. When I was marking it I discovered that the feet would be directly over the spaces between the floorboards so I moved it a bit. (It is still a little off on the starboard side but not too bad.) If I had to do it again I would make the seat 16" wide instead of 14". I think that would solve the problem. Here is an as-built drawing of the stool with a seat width of 14":
The final lengths of the legs will depend upon the exact angle used and the actual dimensions of the boat. They should be cut a little long and then adjusted as needed.