The Superman Long A was tied into starters being used in relief. It didn't fatigue them properly, so you could get a ton of innings out of them. As TJ says above, you could get 400+ IP out of '95 Maddux or even the 2000 Pedro in relief. Set a short IP guy as your starter on a 40 PC pull 5 and have Maddux or Martinez set as Long A with 100+ PC and they'd pitch in 100+ games picking up between 3-7 IP per appearance...
But even this was an improvement over the really early sim that based pitchers salaries primarily off of ERA and had no real concept of fatigue, so Milacki could get 400+ IP easy without fatigue (I seem to remember a few people managing to stretch him up to 800 IP or so). I didn't do a whole lot of leagues back then, mostly just used Sim Matchup and Dream Teams... I was really into the Dream Team rankings and worked diligently at building the best Dream Team possible.