Here's what I believe to be the best treasures to use. At first it may be difficult getting used to an offensive set, but it's definitely worth it. I encourage everyone who's looking to get faster to follow this guide.

Adventure Mode treasures: 1-5: Bow, Shield, Sandals 1-6: Bow, Shield, Sandals 1-7: Bow, Shield, Boots 1-8: Arch, Hammer, Boots 1-9: Arch, Hand, Boots 1-10: Arch, Aegis, Hand 2-1: Arch, Hand, Boots 2-2: Arch, Hand, Boots 2-3: Arch, Hand, Bust 2-4: Arch, Aegis, Key 2-5: Arch, Hand, Boots 2-6: Arch, Hand, Parrot 2-7: Arch, Hand, Parrot 2-8: Arch, Hand, Parrot 2-9 until the end: Arch, Hand/Lamp, Parrot

In short, the reason why you don't want to use defensive treasures is because enemy damage is actually lot less worrisome than you may have thought. In Bookworm, gems are infinitely useful, and it just so happens that word length isn't the only factor in your gem output—the value of the tiles affect it as well. The Arch is incredibly useful because X, Y, and Z tiles are now worth three bronze tiles. The biggest upgrade, however, is the Y tile. As an example, normally the word PARRY will only be worth about 6 letters giving you an amethyst, but using the Arch and the Parrot will yield a value of 9 letters and an ever-so-useful sapphire. Higher value letters = more gems = faster times. The Hand of Hercules serves as an additional damage booster, useful especially in book 3 when most enemies have damage-resistant armour.

As for a few oddities in the treasure list which may need some clarifying:

• It's advisable to use the shield in 1-5, 1-6, and 1-7 because of how crazy enemy damage is without it. 1-7 is the only stage out of three where you could test out the hammer instead of the shield, but be prepared to blow out your health potions, especially if your average word length is high (due to damage scaling). On that chapter, though, the hydras can all be one-shotted relatively easily, so I personally don't see a worthwhile trade-off.
• 1-10, or Delphi, doesn't require the Boots because none of the enemies have a stun attack.
• On 2-3, you're probably better off taking the risk with the Bust because three enemies have petrify attacks, as opposed to only one with a stun attack. Trust me, you'll be needing that 50/50 chance assuming you're relatively low on purify potions.
• For Sphinx, the shield is there so that you can afford to suffer two attacks without needing to heal, should you get bad RNG (a tutorial on how to combat poor Sphinx RNG is in the guides section btw). Additionally, the Arch + Key combination helps because you'll acquire a gem from spelling all five words, which normally wouldn't occur. It may only be an amethyst, but you'll want to be as prepared as possible for the start of the next chapter.
• Lastly, you want to alternate between the hand and the genie lamp once you receive it depending on how comfortable you are with your power-up potion count. The lamp improves the power-up effect by quite a lot, which is very beneficial if you want to get those sweet one-hit KOs. A good rule of thumb is to use it when you have five or more potions, but you should go all-out near the end of the game regardless of how many you have.