The great DM’s here know these reefs so well and plan it so much you’d really be surprised. Maricaibo is not maricaibo - the start points vary by the DM, the group and the plan. The group really dictates the plan.
I think it’s way more difficult to lead a 90 minute dive than any 45 minute one cause yes, you can run out of reef.
I’ve had maybe 150 dives with Aldora trying to learn the reefs - I started out diving with any DM but it quickly became apparent they all don’t drop in the same place let alone cross over the same place - heck, same DM, same reef three days in a row was three different starting points. Aldora has a slight advantage as they can keep you underwater longer, it allows the DM’s to get creative with what they do - if you ended over sand, more than likely it was an experiment gone wrong.
Blue Project is another op I dive with a lot, that Blanca can point out splendid toadfish in a ripping current at 100 yards. She just knows the areas she dives like you walking around your house in the dark - it’s unreal.
Being a DM just drifting along till you run out of reef has got to be miserable - there’s a bunch of DM’s here that really enjoy what they do and put a tremendous amount of effort into a seemingly easy job, most folks just don’t realize it.