I did a single-segment OoT run just today, which was a very entertaining experience. My time was 6 hours 49 minutes 9 seconds, which converts to roughly 5 hours 41 minutes in "real money". I stuck to TSA's 4h57m route extremely closely, skipping the Lens Of Truth and all those other groovy skippable items.
I got up at around 9am - which is stupidly early compared to how late I've been sleeping in lately - and did the run between breakfast and dinner, lunching on some ready-placed bananas. I felt ill and tired through young Link's section, but perked up later. I drafted a friend to occasionally hit A through dialogue while I used the loo.
The time I got sucked. There were huge, huge errors. I was talking to my friend too much during the Fire Temple and just kept making silly mistakes, and missed Volvagia once which cost time, but the first real slip-up was the fact that I DIED at Phantom Ganon. I loathe and despise Phantom Ganon and always have, in fact; sometimes you can absolutely destroy him in three fireballs, but other times you just forget the rhythm and die horribly, like I did. Urgh. Then I utterly mucked up the block-pushing puzzle in the Ice Cavern, and falling into the chasm twice. It took me eight or so attempts to cross the Haunted Wasteland, because I hadn't learned the route adequately. I forgot to get Din's Fire before beginning on the young Link part of the Spirit Temple, and had to backtrack for it. I ran out of magic to cast Din's Fire and enter the Shadow Temple. And I died again at Twinrova. And those are just the BIG errors. In terms of general pace, I think I was running slower than TSA, which is to be expected, as he is better at this game than I am.
Changes I would make next time and advice I would give to others looking to attempt similar feats would be: