As far as I know MC only appears with other S-II's in Forward Unto Dawn and while that's canon I don't think his height I shown directly against Fred or Kelly so seeing as the story is told throughout by Lasky's memory chief may be taller in Lasky's mind due to him being MC the bad ass killing machine where as he never say Fred or Kelly in action crappy excuse I know but as far as lore goes you are correct chief wasn't the tallest strongest or smartest.