I was going to post this on the forum, but looking at how inactive hte player support section is, I'm better off asking here directly. Therefore, I have questions about the ward cestus (Arms and Equipment Guide, pages 6 and 10 respectively).

Ward cestus
Cost: 10 gp
Damage: Special (unarmed)
Crit: Special
Range: melee
Weight: 4 lb.
Type: Bludgeoning
Text: This is a stout leather gauntlet with
a well-forged metal weight sewn into it over the
knuckles. A strike with a ward cestus is considered an
unarmed attack. If you take a Total Defense action,
you gain an additional +1 bonus to your Armor Class,
representing blows you block with the back of your
protected hand. Your opponent cannot disarm you of
a ward cestus. The cost and weight are for a single
ward cestus.

Summary, as I understand it: Uses character's unarmed strike for damage; grants an extra +1 AC when using total defence; cannot be disarmed

Q1) What is it's crit range? I saw some stuff online about it being 1d4 damage and having a 19-20 crit range, but neither of those are listed here.

Q2) Does it actually take up a glove slot, or does it count as a weapon worn over the gloves? Weapons generally do not interfere with a character's ability to equip magic items, so strictly speaking it shouldn't. I imagine them as a covering for your gloves, or even something like brass knuckles

Best case scenario in terms of optimization: In a perfect world, they would not take up the glove slot, would allow for the use of monk/battle dancer unarmed damage, and would have a crit rane of 19-20, which means you're basically paying 10 gold fo a better crit range, which seems reasonable based on other weapon prices. (e.g. flail: 8g, 1d8 damage, x2 crit; longsword: 15g, 1d8 damage, 19-20/x2 crit)

Since they're a weapon, you can also enchant them, so I imagine a +5 ghost touch ward cestus of speedy impact (impact = keen for bludgeoning, Magic of Faerun) or some such. Then we get the necklace of unarmed strikes, keeping that as a +1 (which is included in the base price of the item, and wouldn't stack with the +5 since they're both enhancement bonuses; similar to how the enhancement bonus of ranged weapons and their ammunition don't stack), you then enchant it with something like wounding, collision, and sweeping (Magic of Faerun). That leaves you with +5 ghost touch wounding sweeping fists of speedy and impactful collision (total +15). THEN, you get some gloves of greater mighty wallop, so your attacks are effectively colossal before any of the other size-increasing bonuses.

So let's say there's a level 20 monk using this setup. Base damage is 2d10, so that's now 12d8 because your attacks are colossal. Doubled crit range...

12d8+5+5, 17-20/x2, can attack incorporeal creatures without penalty, deal 1 CON damage on a successful hit, grant +4 to trip attempts, and grant an extra attack when using the full attack action. I can increase the base dice a few more times with other effects, although enlarge person wouldn't count because greater mighty wallop caps out at colossal and my physical size would be larger, which counts first. Let's say I add in improved natural attack (unarmed). That makes the base damage 16d8.
Alternatively, I could do something like +1 sweeping ward cestus of brilliant energy and a +5 necklace of natural attacks enchanted with wounding or impact and speed. The ward cestus itself would be unable to attack undead or constructs, but against everything else it would ignore armour and shield bonuses completely (not natural armour, unfortunately), and still grant me bonuses to tripping, grant an extra attack during full attacks, and either deal 1 CON damage per hit or have a critical range of 17-20 -- whichever I feel would be more generally useful. Against undead or constructs, I still get the +5 from the amulet, as well as the extra attack and special effect. As much as I love brilliant energy, though, I think the previous build is more generally useful.
The caveat to all of this is that since it's a weapon, I'd have to attack with that hand for the cestus bonuses to count (though this isn't explicitly covered in the rules, I'm going to assume that's a thing, because otherwise it would not make any sense at all). Battledancer allows you to make use of TWF for unarmed attacks if you want to go that route, so you'd either have to get two of these things (which are NOT cheap) or have a weaker offhand attack. This means I'd never actually want to USE a ward cestus in this way, because the flavour is kind of ridiculous ("I punch them with my right hand 6 times") and it involves spenind a lot of money on something that the DM would probably take active measures to counter, but I am curious to see what your thoughts on the matter are.
Munchkins, away!