I will have to read up on that thread.
My thoughts on necks...
If you are making a exact knockoff, you would want to make a one piece neck. It's how it's done. You may have to accept that the neck may twist and become unusable and have to make another.
If you don't care for duplication, go with the multiple strips of wood and have a neck that should never twist - there are always exceptions to this.
If you go this route, I don't recommend using the scarf joint to add a portion of the heatstock. I'd take the glued stock and make a one piece headstock and neck.... I can add the maple splines that I used to strengthen that area. The maple is hidden be the fretboard and headstock veneer.
One thing driving me to make the LP #2 copy is the neck. I'd go for a true one piece for originality and use the splines to strengthen weak headstock area.
Oh, I may be able to help with the neck material if you go the sliced route..