I'm building an ES-3 at the moment. From simply putting the neck in the pocket, on my kit I'm getting only hairline gaps. Whilst I fully agree that the design could be better (the neck pitch on mine is such that I haven't got the height available to fit a floating tune-o-matic bridge like an ES-175 has, so I've got to stick with a fixed one), I haven't found it too bad so far. If they increased the neck pitch, then they could make the high end of the fretboard float over the soundboard like a real 175, and have space to fit a floating TOM bridge in. A floating bridge also lessens any worries about the pre-drilled post holes not being in quite the right place to match up with the neck. My neck has no play in it when fitted into the pocket, so I'm hoping that the post holes are close enough to the correct location for the bridge to work. My bridge (a TonePro's 'Nashville' type) will need the post holes enlarging very slightly to fit the post sockets, so I'm waiting until the neck's glued in before doing that, as I then have a means to edge it over by 1mm or so in the right direction.