Whoa! You are getting too much advice for a newer reloader. First, you bought these dies for a reason...what was that?
Redding makes type S dies because reloaders have complained that standard dies are overworking their neck be over sizing before expanding....hence interchangeable bushings. Also, advanced reloaders complained that they wanted to size their neck turned necks without an expander claiming the expander pulled their necks off center.
With bushing dies I recommend you use Imperial case wax or another thin lube. Based on my experience, thicker lubes get in the bushing chamber and force it off center....pain in the butt.
So, I would recommend you take 3 caliper or better micrometer measurements on each loaded round neck. Then average them to one number. Factory ammo is ok. Ideally your cases should all be the same brand. Measure 5 loaded rounds like this. Buy your first bushing as the average of those 5 averages minus 0.004”. Since you are not neck turning, keep the expander in the die. That will force any variation to the outside of the neck.
if you measure case neck runout, you need to measure to inside.
After FL Sizing, measure 5 case necks as shown above. How does this number look? It should be 0.003-0.001” less than the loaded rounds. Try it. Does seating ring the bullets? How is bullet runout? How are your groups? Is there something not pleasing you? Let’s work on it. Feel free to DM.