Spirit Temple - The last full dungeon. Can you believe it?
TSA does a very good job on this dungeon in his 4h 57m run, and you should emulate it as closely as possible except where noted below:
Official walkthrough:
http://www.zelda.com/ocarina/pdf_files/12_spirit_adult_ocarina.pdf
SC 1 -
This trick *might* be faster than pushing the block (~12"), but it requires a stored ground jump, so I don't know. Time it out and see.
SC 2 - Ceiling switch
SC 4 - Five Silver Rupees. Just emulate what TSA does. Reminder: All climbable surfaces in Spirit can be hookshotted.
SC 5 - Hookshot the climbable wall.
SC 6 - Mirror-turning
SC 7 - Obviously, your hookshot won't be long enough to reach the chest on the other hand, so use your hover boots. Also, instead of longshotting the torch on the third floor, you're going to have to aim for a hookshot target that's right below it.
SC 9 - You'll have to push the switch to kill the Anubis, as you have no fire arrows or Din's Fire...
SC 10 - Get an Armos to stop on the blue switch.
SC 11 -
Iron knuckle skip. It may turn out to be unusable because the iron bars would remain when you return. In any case, just try it out to see if it works--if not, then just defeat the enemy using regular methods.
SC 12 - "Let it shine!"
SC 13 - Use your Hookshot to reach the fourth floor.
SC 14 - Play the Ocarina one last time, and make it your best. :) To get the boss key, step in front of the flames and press A. No damage boost is needed, but timing is crucial.
SC 15-19 - Straightforward mirror manipulation. Your crouch stab should be preserved up to the "boss" Iron Knuckle (she has 40 HP instead of 30, so don't be alarmed if it takes 10 hits instead of the usual 8...but if it takes more than ten, something's wrong!)
BOSS - I strongly believe using Z-targeting on the witches in the first phase is faster than aiming the fire/ice streams yourself. Just try it out and see. Use luck manipulation for the witches to put themselves in optimal positions. In the second phase, stand as close to Twinrova as possible on the third spell. Press A as you jump over to the boss (with Z-target on) and follow up with five crouching stabs. One cycle is easily doable even in an unassisted run.
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2h 40m by TAS timing conventions (power-on to final input) is a certainty based on times extracted from TSA's run. If we were to tack on TSA's work following Forest, we'd end up with around 2h 41m. A 2h 30m based on SDA timing (Link's house to final blow on Ganon) would be a good goal to strive for. Good luck!