Finished Master Mode Trial of the Sword today.
Middle Trials, despite being the easiest on Normal, were somehow the hardest on Master. I think it's a combination of the lack of good weapons with much quicker enemy scaling that does it - especially in the wind section, where bombing enemies is hard. Like, a Red Bokoblin with 13 HP dies to basically anything nice and easy. A Blue one with 72 HP? That's like 4-5 Bombs, and they need to be delivered with little gap between them or else they heal. Black is up to 240 HP compared to a Blue's normal 72, so they eat through weapons, and have a greater chance of getting flung off the edge - which means you don't get their weapons.
After the wind section, the dark section is pretty scary on Master as well, due to the increased enemy detection it can be hard to bait and kill like you might do on Normal. And after that, the Guardian Scout section... everything there is one level higher, and that means a TON more HP for basically everything. Those 13 HP Guardian Scout I's you OHKO? Now 375 HP Scout II's. And those Scout II's? Now 1,500 HP. In the second room of the Scout section, I used up about 2/3rds of my weapons. And in the room after that I had no choice but to bait and push everything into the water to kill it.
The Final Trials I cleared first try, was half disappointed with them. The Lightning section is easy. The fire section was also easy. Also I found out that the one chest I despawned by somehow pushing it through the ground? Had Ancient Arrows in it. Pretty annoyed about that, 3 more Ancient Arrows makes a big difference. The cold section... I think you get a bit more warm food than in Normal mode, and you probably need it since it takes longer to kill everything. But this section also had the hardest enemy in the trial - a Gold Moblin. Never mind the White and Silver Lynels, this thing... just use an Ancient Arrow, okay? He's not worth the hassle. Massive damage to you (I think he has a 27 might Spiked Moblin Club, and 48 base attack means... 75 attack? So 18 3/4 hearts per hit), recovers quickly, elemental resistances all around... just don't do it. Final Guardian section is easy if you use Ancient Arrows wisely. Lynels, Skywatchers, Stalkers, Turrets. There are 8 of those total, plus the Gold Moblin, that's your 9 Ancient Arrow allotment. I actually killed 1 Stalker and 2 turrets without them so ended up with 4 Ancient Arrows left.
All in all, it was fun. I did the whole thing on a max of 15 hearts, which mostly only hurts for the Final Trials because Hearty food (in short: Eat Hearty food before going in to get to 30 max hearts anyway. After that you're still healing the same amount from food inside, so it doesn't really matter if your max is 15 or 27. The Final Trials are an exception because you get 6 Hearty ingredients, so can make up to 6 Full Health +1-3 extra heart meals, and of course more normal hearts means more healing from them). But the final trials aren't too hard anyway so it doesn't matter much.
I'm going to enjoy finishing off the rest of my Master Mode playthrough with the powered up Master Sword. Honestly, the fact the beam costs no durability might be my favourite part of the full power Master Sword. Means I basically have an unlimited use, 20 power Magic Rod, that delivers a decent amount of stun on enemies.