Sure, there are nearly infinite ways to get from point A to point B and if I already had those dies on hand that would probably work. I still fail to see how using full length dies from other cartridges to size only the neck is any different than using stepped bushings to size only the neck? Am I missing something?It really seems like you're over thinking this. I'd just use a 6mm BR die to go down from 6.8 to 6mm, then run the brass into a 224 Valkyrie die held off the shell holder far enough that it only sized the neck. After that you can use your 6.8 SPC die with whichever bushing you'd like to get the neck tension you're looking for if you needed to. Your brass could be ready to load and fire in two press strokes.