Re: Load Variations with different brass.
The REM brass will be way heavier than the Win brass (read less powder capacity, higher pressure, softer brass). You will see more pressure increase due to the case volume than you will due to the increased neck tension.
The nickel cases will show signs of "dirt" more so than brass. (read scratches etc).
The nickel cases will be a bit harder than brass and may "shrink" back more or expand less, depending on how you look at it, when the sizing button is pulled through the mouth.
With my nickel cases I have turned the necks to achieve uniform thickness and resulted in greater thicknesses than with Winchester cases.
Just my experience.
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!