I know summoning skill affects duration, but this is the first I've heard of it affecting potency (i.e. damage mitigation from the stoneskin, acc/eva boost, MAB boost, haste%, etc. etc. - I thought all those were flat-rate, or varied with moon phase for Fenrir and game time for Diabolos) or offensive damage output. Linky to tests or more info?
Anyway yeah, macros 4tw. Macro in Antivenom with your rest macro (along with Dark/Pluto's Staff etc. and the obligatory "/heal on" of course), macro in Summoning when you use any blood pact (or at least any buffing blood pact).
If you're tight on cash such that you can't get both, your options are:
- Get neither and save money or spend it on something else.
- Get Summoning Earring from repeated ENM attempts.
- Same as above, but buy Antivenom Earring too.
- Get Antivenom Earring from repeated Mamool Ja Training Grounds assaults.
- Same as above, but buy Summoning Earring too.
- Get *both* items directly from source.
- Go do something or other for gil income, and then buy both items.
Point being, you have options, so you don't really have to *choose*. (Besides, you've got two earring slots, what's in the other one?)