Added damage vs Ele Pen Calculation

I wanna craft boots and have to pick one of the Following Enchant

Either Damage Penetrates 10% of Enemy Elemental Resistances if you haven't Killed Recently
or Adds 1 to 160 Lightning Damage if you haven't Killed Recently

PoB shows me +4,5% dps with the added damage and nothing with ele pen.
I assume its bc of Penance Brand is a Spell that dont hit.

But in general, how can i calculate it in PoB?
PoE Wiki says "depends" so i would calculate for certain bosses.

Does 10% Ele Pen means if an Enemie had 50% Ele Res its -10% = 40%?
Or 10% of 50% = 45%?

Ele pen wont do anything because you are an Inq with the Inevitable Judgment ascendancy and also going crit.

Which means your hits will ignore ele res (aka res = 0) and nothing will change that. No ele res curses, pen, exposure or whatever else you could use to manipluate enemies ele res will have any sort of effect.

Youre right.
But thats why i asked for "in general".
Have other builds i want to gift enchanted gear.

You can add custom modifiers to gear or in configuration tab in PoB. You can also simplify them, like "adds 1-160 lightning damage" instead of the whole text.

penetration entirely depends on how much of it you have, as it is a sliding scale of effectiveness. Generally though, its going to be better

You can look at the penetration poe wiki and see this curve:
https://www.poewiki.net/wiki/Resistance_penetration
You have to read the chart in reverse.

What that means is:
Penetration has diminishing returns on actual damage % the more you stack it.
It loses "effectiveness" if the enemy has less resistance to begin with.
It changes effectiveness depending on the enemy.
BUT it has super super high damage effectiveness against the monsters you NEED it for.

A very quick and dirty way (mildly inaccurate) you can calculate which is better for your specific build: add up all your sources of flat added lightning damage, min and max. Add the min and max together and divide by 2 to get the average. Now, make that the denominator and put 80 ((1+160)/2) as the numerator. What decimal do you end up with? If it's higher than .1, then "1-160" is going to be GENERALLY stronger than the penetration.

Ex:
1) Flat lightning from Arc @ lvl 20: 198 - 1122 = ((198 + 1122) / 2) = 660
2) 80 / 660 = .12. Likely stronger than 10% penetration against most enemies.
3) BUT.....you are likely going to have far more than just the base flat lightning damage of the skill to work with.

Thank you for your explanation.
Unfortunately, I have suffered from a genetic disorder since birth, which manifests itself in nausea whenever I see two numbers close together that seem to be mocking me.

I just assume that flat damage is potencially better than res pen.
Esp since it interfears with other reductions and various monsters that dont even have resistances or too little to make a difference.

Should never have started this topic.

I'll make it simple for you

10% ele pen will outperform 1-160 flat on near any hit based build not using resist shenanigans/omni. if 1-160 looks good your base damage is already low and on spells you'd certainly get more out of gem level sources. 10% ele pen boots were the expensive enchant boots prior to their removal 1-160s were relatively cheap.

and in your examples its the first one just take 10 off their stated resist value (for hits only)