The beauty of the Lee Collet system is the cost factor. For nominal cost one can make ammo about as concentric as a near $300 competition die set with neck sizing bushings, no need for an expander.
With those dies the sizer sizes the case body, the neck sizing bushing can be changed to get the perfect neck sizing without needing an expander.
The seaters are precise with micrometers. Now, as noted earlier, I’m not overly impressed with Lee seaters. They’re hit and miss. With some rounds I use a better seater, some with floating bullet guides.
And I do check concentricity with a Sinclair, correct run out with a TruAngle tool.
DF
