That's a good shout, I've also been using Mageflare Runes for Shimmera. I've reached around depth 380 now which is promising!
I agree with the math turtle, with the gems and quartz giving more shield stacks, navigating Underbark is really fun. Even in early biomes, you have to choose between shield stack, restore cells, and the most efficient path (digging straight down). In the late game, the early biomes are easy and almost mindless for most turtles, so I appreciate the challenge turtle of Nix.
I like your Shimmera suggestion since we need the opportunity to stock up on opal and etc for the Umbra layer. I think it'll be thematically nice too since it's the shiny light layer and the shiny light turtle.
Also more tips for interested people: don't try to change boots mid run (my instant stamina drain rip), and you can refresh between Meadow and Farfields until you see a spawn with more quartz.
