Make sure the vertex weld actually worked by selecting individual verticies using the Click-and-drag selection, like you would to select more than one, but at one point, if it says you have 2 verticies in that point, the weld didn't work high enough.
Since you're using 3DSMax, and I know how to work it, I'd say to select the whole model in Polygon selection mode, and auto smooth at 70 degrees. That smooths out any rough corners.
Nice job! I'd like to think I inspired you to do this on you're own, I'm probably not, it's all good. Nice start!