Firstly, the growth chart I've been using has been Egg->Baby->Larva->Grub->Cocoon->Adult. I can't be certain if this is how it actually is, but if you're familiar with the movies it makes the most sense. As well, most logs and guides I've come across have either described the Larva->Grub transition, or the Grub->Cocoon->Adult transition.
Anyhow... I've been trying to keep my Mothra Larva at minimum weight. After she'd been a Larva for a few days, I decided to use logs to get an idea of growth times (I'd always pause her due to never being up early). A few of the logs I looked at said the Larva->Grub transition required a high weight. I was skeptical, as the guides all stated they'd "heard it somewhere". My Mothra is currently 5, and still a Larva. It's possible that it just hasn't been long enough (never clocked over 8 hours in a day), though I'd still like clarification before I gorge my Mothra Larva.
Anyhow... I've been trying to keep my Mothra Larva at minimum weight. After she'd been a Larva for a few days, I decided to use logs to get an idea of growth times (I'd always pause her due to never being up early). A few of the logs I looked at said the Larva->Grub transition required a high weight. I was skeptical, as the guides all stated they'd "heard it somewhere". My Mothra is currently 5, and still a Larva. It's possible that it just hasn't been long enough (never clocked over 8 hours in a day), though I'd still like clarification before I gorge my Mothra Larva.