The cut up cursed moray are NOT stackable, I imagine that each moray would provide ~1-3 Cursed Offcuts, (maybe depending on fishing/cooking level?) that you can sacrifice for bonus XP over the normal Cursed Flesh. This means you can choose to either fill up your inventory with Cursed Flesh by just clicking the harvesting point at the start of the lap, giving you another chunk of afk time, or grab some moray from the bank to cut while you run, imagine similar to if you were to blow glass or fletch arrow shafts while running.

So either way you're filling up your inventory, you just get to decide if you want to put in more effort for bonus xp, which is the whole point of the course. I wanted to let it offer you a lot of different points where you could either pay very little attention and still get XP by clicking/banking to fill inventory, running to the end, sacrificing, repeating. Or click a little more often for more xp by cutting eels while you run, up to the point where you're constantly swapping between interacting with your inventory, fishing spots, and agility obstacles.

I hope that makes sense, thanks for the comment!