Quote Originally Posted by The Blind King of Bohemia
Eric McGeer, quite the expert on Byzantine Warfare in this era, actually questions their overall effectiveness and suggests they probably went out of use after the war with the Fatimids in the 990s. Though extremely hard to get hold of, his book, 'Sowing the Dragon's Teeth: Byzantine Warfare in the 10th century' will tell you everything you need to know on the subject. It also features Phokas' Praecepta Militaria and Ouranos' Taktika.
Excellent book. Recommended.

The typical recommended formation was 504 men depending on numbers available (a 380 man formation is also recommended in the manuals),
Ah thanks. I was wrong about 570. I knew there was something about 500.

Also, lancers were never really in the front line, it was usually the macemen and sabre holders, the shock troops as it were. Lancers were either on the sides or near the back, the Byzantine Kataphractoi did not seem to use it in the charge, since they did not actually charge.It is unanimously agreed that they always trotted, never charged.
Tzimiskes sometimes used charging, but it was rare, true. And lancers were in the front line too, but they weren't too often, because the massivity of the horse/armor/warrior package was far too heavy to sustain a thunderous charge with lances.