I lubricate the case well with a fine quality lubricant, not a spray, and carefully run the case into the full length sizing die. Clean the lube off after extracting the case from the die, measure and trim. You will loose a few cases to collapsed walls and creased shoulders but it works well. I found that R-P cases were easier to form and I had fewer rejects, maybe because R-P cases tend to be slightly thinner in the upper walls.
You will experiment with techniques and develop your own way of fine tuning the operation.
Good shooting!!!!!!!!