The thread has probably become too long to follow, but a lot of the info is there: smoke appears to be from oil, carb is rebuilt,new plugs/coil/dist cap/ wires/rotor. 1st oil change had a lot of water in oil, second one a bit less.
I think a sensible approach would be to do the valve stem seals, since they are relatively inexpensive, and then check the head if smoke continues after that.
