This would be such an easy fix. right now at checkpoint 4 they have 2 lines for TSA-Pre and 1 for SP. Just change it to 1 line for regular TSA-Pre and 2 for SP. In the SP line, split that off to either regular security or TSA-Pre if you get the 3 beeps.
Half the reason TSA-Pre line is so long is because non-elite travelers don't know the rules and end up slowing the whole line down.