From talking to the guys at Woodchuck den,Neck turning isn't neccessary.All you have to do is first use the forming die,and then the regular dies,and you are good to go.
You guys be very careful about neck turning on wildcat cartridges. Check the specification on the case. If you turn the case neck too far below the design specification you will shorten the case life due to overworking. Everytime you fire it, it expands. Each time you size it, it gets compressed. Each time you run that process, you "work harden" the material. Eventually, they split. If the cartridge is designed to have the neck compressed from a standard case, turning the neck can only hurt the performance and the case life.
What Danr Said!
Better look into this with the designer of the cartridge with case specs OR a reliable source.
I only turn the necks on cases I form from .308 cases when I make them into .243 Ackley Imp cases.