Didn't see a direct response to this part of the question so - shoot it again, no need to toss it.
Re: length of neck sizing. That's how the die is designed. Redding goes so far down this road as to make micrometer adjustable neck-only bushing dies to pair with a body die for even more precise control over length of neck sized.
To really maximize the utility of this kind of die, you need to set the die high and shoot the case several times until it won't rechamber with neck sizing only. That means your shoulders have moved as far forward in the chamber as possible, and you can then set the lower half of the die for correct shoulder bump. Until this point it's normal for about half or so of the neck to not be sized while setting the die high.
Once you get the shoulders et, then you get into setting the upper half of the die for length of neck sized. The point of Greyfox saying he screws the collar down until he can just hear the bushing click around is to still let it float without putting the bushing in a bind, that will get you the most length sized that the die can do. You can adjust outwards from there if you want, or leave it where it is.
Different brands of bushing dies will leave different lengths of the neck unsized, it really just depends on how deep they cut the space for the bushing. As previously mentioned SAC makes combination neck/shoulder bushings to resize more of the neck while still giving the tension control of incremental bushings if you really want the full neck length sized.