They work in conjunction with one another. Someone mentioned something the other day and I did something similar when I first started.
Remove all your pitchers with less than 45 control or 50 splits.
Add up control, splits and P1-3 for starters and P1-2 for relievers.
Stock your staff with the highest totals.
At some point, when you feel comfortable with pitching, experiment with the lower control/higher splits-pitches or higher pitches-control/lower splits. You'll figure out which weaknesses can be overcome.