I got my big armatus to take massivore pellets. I started with dropping feeder in the same spot ONE AT A TIME.
Once he get used to that, I started to feed semi thawed CHOPPED shrimp (they don't sink right away) at the same spot. I'd throw a shrimp then feeder, then shrimp, then feeder. He can swallow a smaller pieces of shrimp right away, if it's too big, he'd have to bite it and "think" about not swallowing it.
He ignores the shrimp for a few times, but after a few days, he started to bite the shrimp, then spit it back out. From this point on, I would do shrimp, shrimp, then feeder, then shrimp x 2, then feeder.
After a couple of days, he should take the shrimp, as soon as he started taking the shrimp, STOP the feeder immediately.
From this point on, it's pretty easy, I started stuffing the shrimp with pellets for a few weeks then before you know it, you cna drop a pellet and he'll take it right away.
The key is patience and consistency. Most of us only have one of the two..
stan