I know some prefer to neck up to 338 or 8mm first, and then to 35. I don't. I just run it through my redding die, but I do highly recomend annealing first, especially if the 06 cases have been previously fired. It helps reduce neck splitting. Don't worry too much about the 06 cases being too short, they will lengthen in time, unless you are shooting a 35 Whelen AI.