Is it known if Rimuru's magicule supply is growing rapidly?

Question

Rimuru, the protagonist of That Time I Got Reincarnated as a Slime, has powerful magical abilities. In that world, "magicules" are basically particles of mana and are the fuel for magic. In two episodes we see him depleting magicules to below his minumum reserve point, at which point he shuts down for three days. When he awakens, his supply is fully restored.

In episode 3 he names about 100 goblins and, lastly, the direwolf alpha. (Later we learn that naming the alpha (Ranga) allowed the name to be shared by the entire pack.) Then he shuts down due to insufficient magicules. In episode 6 he names about 500 more goblins before shutting down. Even if naming Ranga counted as 100 named wolves, that was still only 200 total beings named the first time.

Could he actually store about 2.5 times more magicules after about 10 days? That is the simplest explanation for the greater feat. If so, is it known if his magicule storage continues to grow at that kind of fast pace?

A second possibility is that, in the first instance, simultaneously affecting a whole pack acted as sort of a short circuit on magicule usage. Doing it one at a time might have used much less total. This case would not require the kind of magicule storage growth seen in the first.

A third possibility is that as he learns to use his abilities, he gets more efficient in using them. So the second time he could accomplish a lot more with the same amount of magicules.

A fourth possibility is that I'm way overthinking this...

Answer 1

Episode 10 offers a pretty definitive answer regarding the example that prompted my question. (Link should become freely available (with commercials) sometime 10 Dec 2018. As I post, you would need a Crunchyroll subscription to watch ep.10.) First I'll state that nothing in the anime so far has indicated Rimuru's magicule supply is growing rapidly. His number of skills continues to increase, but that doesn't mean he has significantly gained in magicules (i.e. mana).

I'll again hide the example info as a spoiler Since it includes definitive info from the series.

The stronger the monster being named, the more magicules it takes to name them. Goblins are near the bottom on power level, so naming 500 at once was doable. The first time though, naming close to 100 Goblins and, as it turned out, 100 Direwolves, used up all his magicules because Direwolves were stronger than Goblins. When he names just 6 Ogres in episode 10, that pretty much depleted Rimuru, more than either of the previous two naming sessions. Ogres are considered very strong.

Answer 2

I think there's another possibility: The more monsters he eats the more his magicule storage grows.