Hmmm... it basically adds the same amount of DMG when in reguard of multihit.
It adds 0.1ftp to the first hit.
So it adds 0.1 X Mod X pdif(cratio or w/e ya use for atkvdef)
Makes no odds if the weapon does more hits.
For example guillotine vs torcleaver increase
Torcleaver is easy 0.1+4.75 = 4.85 a 2.1% increase in DMG
For guillotine is 1 hit at 0.85 then 3 at 1.0 so overall it's (0.85+1.0+1.0+1.0) X Mod X pdif
so u can consider the ftp of Guillotine as 3.85 and +0.1 to that is a 2.5% increase
And yes there Da and the acc bonus to consider but just saying it's a single hit as your reason isn't really justified.
Imo it comes alot more to do with the mod and base dmg of the the weapon.
For example to add 2% to Torcleaver with 110 DMG and 100 vit overall u'd need
110 + 0.6(100) = 170*1.02 = 173 base DMG
3/0.6 = 5 VIT
Which prolly mean Apathy collar (9VIT) will beat the gorget unless i missed something and alot of numbers were estimates either way w/e not that fussed
And Ganesha's Mala prolly is the best overall since it has 4 VIT and 2% Quad attack
2% quad attack = 2% chance to add 3.00 ftp to a weapon (basically)
2% * 3.00 = 0.06 (so just under what gorget adds but the 4 VIT prolly makes up for it)