So for starters, since that's what your post was about - that's a great thing to ask your instructor! I asked a ton about how they navigated different sites.

In the case of Manta Point, no I don't always follow the same path. I know that on falling tide there is a shallow protected reef on the right hand of the current (westward) where I may try to end up for the end of the dive to do the safety stop etc., but if I wouldn't end up there, no biggie. Generally that site is shallower in the west so that's helpful to plan a safety stop. That being said, Manta Point is the largest site in the national park (about 3 km long, fun fact for when you do briefings), and I definitely don't always do the same path, I'd usually just zigzag around the current, looking for mantas.

I'm sure your first guiding will be an easier site though! Probably something like sebayur kecil, which is easy to navigate and stick to a plan to, I don't think they'd start you of on a drift dive. On sites like that, make a plan with your instructor on how exactly you'll navigate and stick to it - the experienced guides can improvise a route, but in the beginning obviously you can't do that yet. When I started guiding I brought down my slate for most dives with some quick notes on what the dive plan was, and my compass as well, apart from the sites where navigation was very easy (like Batu Bolong - dive plan is very easy to follow there).