You can use 24/63 pitchers in tandems or long releif and if you have enough of them they can help eat innings if needed. Putting them in tandems gives you more control over when they pitch, but unless you check every cycle and move them around you'd likely get more innings out of them in long releif (assuming they pitch every time they are not below your fatigue setting)
You can also use tandemB settings to make sure a certain RP always gets the first call. Its like having a third category of RPs Setup A ,B and C. But again, you have to check every cycle and move the scheduled starter to the Tandem A spot and the preferred RP to the Tandem B spot. Lot of work over 162 games but useful after roster expansion callups to maximize innings for those future closers.