What is your other set? Neither are particularly great sets. And if your other set is a trials set, then its an easy "no" to False Gods. And my instant reaction to New Moon was "why would you run that over Order's Wrath or War Maiden, unless you really need the penetration buff?"

Its kind of hard to answer this question without knowing what your DPS is as well. A parse on a non-trial dummy. Easiest response is to try both out in a parse and see which works better for you.

@eMKa8 This gets very confusing and I don't understand all of it, especially the theorycrafting/math part of it. But the basics are, on a traditional PVE DD group build, between penetration and crit you want to build near the cap, taking into account buffs and debuffs from the group, without going over on either. If you go over, its a wasted armor buff. You can also increase both through CP and mundus stones.

By no means am I claiming to be an expert, but just imparting my understanding of PVE group DD builds. I expect others to chime in to correct me or add to this.

8K penetration is just fine. The penetration cap is currently 18,200 for group content. The tank in group content will provide debuffs to lower that number on the target, typically by about 11K, leaving 7K and change. Your 8K should overcome the remainder of the penetration on the boss.

Crit damage is the primary focus of PVE group DD builds. The crit damage cap is at 125% of damage that can come through one strike. I think the max crit chance number is 21,912, which would give you a 100% chance at a critical strike. The set bonuses, like 657 for 3 pieces of Mother's Sorrow divide into 21,912 which will give you your percentage chance increase to critically strike. Yes, its confusing.

Mother's Sorrow is a massive crit set. If you pair it with another big crit set, like Order's Wrath, then max out on CP for whatever damage you want, your crit could be north of 60% unbuffed, which is high. You would likely run the chance of going over the cap in a raid group (trials) but not so much in an average dungeon/arena group. So that's good.

25K on what I am guessing is a 6m non-trial dummy is pretty solid. With that, I think a flat percentage damage increase would work better. Of the sets you mentioned, I would choose False God's over New Moon. I am not a fan of New Moon. Just don't like it. Others do, and that's cool. But I think given the content you are running, False Gods is a better call.

If I could choose a different trials set I would go with Whorl or Ansuuls, but that is a different discussion.

This is a video explaining combat metrics and damage (an add-on for PCs):

https://www.youtube.com/watch?app=desktop&v=BhDt5_1OFsU

The add-on is very helpful to break down where your damage is coming from. I, unfortunately, play on a console, so the crit damage I see are the orange numbers in the middle of the fight. If you see orange numbers, you are inflicting crit damage.

But crit percentages in a parse are not the same as your build. To use an alcast magicka templar build for an example, the setup page shows spell and weapon crit at 52.6% unbuffed. The second slide is 63.6% buffed, with buffed being Raid Target Dummy buffs (here is a list of all of the buff/debuffs https://www.eso-u.com/articles/guide_on_target_dummies), buff food, Spell Power Potion, Weapon Damage Enchantment. But also, his spell/weapon damage goes from 3887 to 6335 buffed with his penetration at 6335.

https://alcasthq.com/eso-magicka-templar-build-pve/#

Those crit, damage, and penetration numbers can vary if you run in an organized trials group, depending on what the tanks and healers are running, and can go higher with proc sets and other sources of crit damage (and penetration). I know alcast has his fans and detractors, but as you can see, even he is not building a massively high crit DD that exceeds the 60s, or a high penetration build, because both will hit the cap in an organized trials group.

Your 54% unbuffed crit chance should be fine. As is your 4K spell damage. You can raise that (and weapon damage) through potions, CP, gear sets, mundus stones, and through healers & tanks in group, for instance Molten Armaments (DK tanks). Daggers will also add crit.

Lastly, check out Skinnycheeks. He has a really solid variety of builds and explains what is good for different content and play styles.