Braking is type specific. The 744 with 16 carbon brake units brakes very differently to an aircraft such as an A320. I can't remember the actual figures my company used, but the in flight figures available assumed a wet runway and using autobrake. The only difference was that we would tend to use 2 for a dry runway and condsider 3 for a wet. IIRC, the figures didn't metion full reverse, so the policy of using reverse idle was used. And the accident report alludes to the fact that the Qantas flight training department was teaching this as well so it's safe to say that it was Qantas SOPs. The crew thought they were landing on a only wet runway - so they used their SOPs. Had they realised that it was contaminated (the clues were there) the procedures would have been different.
My comment was to point out that use of reverse idle is common on 744 pax operations.
I have studied this accident thoroughly as well - I was flying the 744 at the time and a friend of mine was part of the subsequent Boeing inquiry. I would say that as in most accidents there was a chain of events leading up to the crash and it could have been broken at any time. But the Commander's decision to stay on the runway was the main cause. If the PF had initiated the GA correctly by pressing the TOGA buttons, it probably wouldn't have happened, but the Commader's closing three of the thrust levers sealed it. The PF wasn't aware that the autobrake had disarmed when he advanced the levers and his slow recognition of the lack of decelleration, lack of the use of reverse thrust having landed fast and long meant the eventual outcome was almost a certainty.