I neck size with a Lee collet neck sizer, when I need to bump the shoulder back, I use a RCBS FL sizing die with the de-capping rod removed. I bump shoulder until I just feel resistance closing the bolt. Does this make sense?
You can also size only part of the neck with the Lee Collet by using a washer on top of the shell holder
It leaves part of the neck unsized the width of the washer
You can Partial Full Length Resize by setting your gun up and repeatedly chambering and resizing the cases until the crush fit just barely goes away but you also get a lot of useful info from the Headspace Gauges. It is easier to check a whole loading block of cases to see which ones might need to have the shoulder bumped, especially if you are using cases with a different number of firings. And it will give you info on your chamber headspace (or head clearance in a belted case), tell you how consistant the dimensions on new brass is and then make the shoulder bump process more precise.
I use the Hornady set that goes on the calipers and find them very useful.
I like to reach the point where the crush fit is all but gone and with a very slight crush fit if any. That way if one of the cases has a little more springback then it doesn't get tight in the chamber and will chamber in the field without fail despite warmer weather expansion or minor detritus. I do want to hold the case between the bolt face and chamber shoulder but not tightly.
I also like to get rid of the 'crush fit' feel, as I've never had the best accuracy when I could still feel the bolt close against the brass. That is why I measure my shoulder setback, so I can be consistent from reloading session to reloading session. This also lets me make sure that once fired brass is resized the same amount (sometimes requires different die settings due to springback) as brass that has been work hardened during multiple firings.