I'm in 'home stretch' of finishing the 'rowing version' now, and I too plan to add the sail rig at a later time.  Yes, it does appear to be as easy as it's advertised.  There's a hole in the forward seat (thwart) where the mast will pass through, and you also have to build a small mast step on the floor of the boat (under the hole in the fwd thrwart) to seat the bottom of the mast.  You also have to cut a hole in the middle thrwart for the daggerboard and it's trunk - all of which takes place during the building of the 'rowing version'.

I am building a sail rig for my EP and would like some advise on attaching the halyard to the gaff.  The intructions don't specify the best method for making this connection and I can't make out how other builders did it upon reviewing pictures posted in the photo gallery.  I was thinking about drilling a hole through the gaff and running the halyard through it, but was concerned about weakening the spar. 

Similarly, while the instructions say to just tie the sheet around the boom, I would like to attach a block near the clew and another near the middle of the boom to run the sheet through.  However, I don't want to weaken the boom by drilling a hole in the middle of it.

Any thoughts?  Or better yet, clear pictures showing these connections?