The Redding FL S die can be used as a body die when the decap rod & bushing are removed. The neck can then be sized with the Lee Collet Neck Die.
The collet is said to produce less run out? Needs testing.
The bushing should not size fired brass necks down more then .008" in 1 step (Redding info)
I just bought the Lee 243 Win. collet die. No tool to check runout.
What I don't like is having to apply over 28 pounds on my Rock Chucker 2 press lever. Lee said this puts about 600 pound pressure on the ram. This will wear out any press, sooner then later. IMO.
My 243 collet mandrel measures .240" in diameter. Neck tension is .0015" after sizing. At age 76, this is just to much effort needed to neck size. Plus its an extra step.
To get the same neck tension every time with the Lee collet, some device is needed to measure pressure applied to the lever, when sizing.
A quick test, bushing VS collet, has the bushing producing better groups on target. More testing is needed.