A Summoner's Gear Guide

does sroda earring work like that as well? I'm guessing the ring is raising the avatar's weapon rating to affect all hits.

@long_horned explained how to calculate Volt Strike damage some months ago.
https://twitter.com/long_horned/status/1569730222634987520
They are calculating Volt Strike and other physical pacts damage this way:
(Avatar Melee DMG+fSTR+Stat Modifiers+Blood Pact Damage Job Points)*fTP*pDIF*Critical Hit*Crit. Atk. Bonus II Trait*BPD

Melee DMG is 132 for a lvl 122 avatar, Sroda Earring fits here
fSTR (Avatar's STR vs enemy's VIT) caps at +24
Stat modifiers:(309 STR+292 INT)*0.2*0.85=102
Blood Pact Damage Job Points 20/20 adds +60
fTP is 5 for Volt Strike
pDIF (Avatar's attack vs enemy's defense) caps at 4
Critical hit and Crit. Atk. Bonus II aren't very important and are ignored in certain zones when pDIF is capped
Avatar Lv.+1 from the JSE earring adds 1 melee DMG, 8 attribute stats and 11 magic damage.

Avatars's stats, melee DMG per level, fTP and stat modifiers of most Blood Pacts can be found at this address: https://w.atwiki.jp/bartlett3/pages/329.html
It also show how to calculate ranged, hybrid and magic pacts. It's very accurate, I tested Crag Throw and Burning Strike damage and got the expected results.


tl;dr
Physical pacts: Lugalbanda > Sroda/JSE+2 > JSE+1 > JSE > Gelos
They say Sroda beats JSE+2 but in my case with my own gear/ML JSE+2 is superior by a tiny amount. Both earrings appear to be very close. JSE gives a lot of atk/acc too.

Hybrid pacts: Lugalbanda > JSE+2 > JSE+1 > Gelos/JSE > Sroda
Sroda falls behind due to BPD being calculated twice.

Magical pacts: Lugalbanda > JSE+2 > JSE+1 > JSE > Gelos