Although I don't know the trick behind using WED for the basic shapes, what I tend to do is place a mess of vertices off the side then move them around to form the basic shape, performing lots of rather simple calculations for maximum accuracy along the way.

I think the cause to the gap is that the vertex in the close center top area isn't joined up properly. A quick fix is moving the vertex. As to the texture stretching, this might be from in WED or the conversion to MED. Open the skin edittor and move the vertices to adjust this. Want me to build a quick sample of a similar shape?