If i had the consistency you have i wouldn't accept big mistakes in the begginning of the game, because i always feel like, if i do a big mistake in the beginning and carry on with the run and all go well, i will always think the run is stainned and why i didn't reset. That's a little different from a big mistake in the end or middle of the game i think... Well, that's what i would do, but don't take me bad, i know you have your reasons, and i'm trying Segmented anyway, so it's probably different. Good luck with your run!
Btw, i was thinking of a strategy for the first metroid's room in Torian, don't know if it would work but maybe you can give it a shot and see how it feels. Basically it's the TAS strategy, you handle the first metroid the same you've been doing, the difference is the second one. After killing the first metroid and cancelling the Super Missile selection, quickly shoot the beam and jump from the ledge, and while in the air, quickly select the Super and shoot in the metroid that should be frozen. If it works and you still have time in the air after cancelling the Super Missile selection again, you can try to freeze the third metroid while in the air or landing on the ground.
Btw, i was thinking of a strategy for the first metroid's room in Torian, don't know if it would work but maybe you can give it a shot and see how it feels. Basically it's the TAS strategy, you handle the first metroid the same you've been doing, the difference is the second one. After killing the first metroid and cancelling the Super Missile selection, quickly shoot the beam and jump from the ledge, and while in the air, quickly select the Super and shoot in the metroid that should be frozen. If it works and you still have time in the air after cancelling the Super Missile selection again, you can try to freeze the third metroid while in the air or landing on the ground.