#steel soul 3

This sedic slash allows you to not clip the ledge on the way down, saving 0.18.

0 soul strat for the first 3 spiders in the big darkroom. Works on every rng as far as I can tell. Clips cover both rngs for the 3rd spider and pretty much every rng for the first 2. Be sure to go neutral for the dashes before the 3rd spider.
In terms of timing: For the first 2, you should do this. Fireballing is slower and nothing else is consistent. For the 3rd spider, it loses about .15 to just fireballing, (think it depends on rng though, if 3rd spider is left then this strat loses slightly more?) And loses about .4 to just sending it. Wouldn't recommend

Dunno if known but this is like by far the fastest thing here, seems to save .25ish, maybe slightly less. Dont do this on 1hp, it loses .4 to get hit left by the hatcher but that's still worth it. It's kind of precise for what it is (which is why the jump is required before the pogo) but 100% worth going for