By Lakshmi.Zeosilot 2013-01-01 22:23:35
Completing magian trials via the use of Astral Flow is a very possible strategy which I myself have utilized; however, it is very much a team based effort.
I will attest to what Innina said in regards to Astral Flow dropping the HP of enemies down to roughly 30~40%, easily more than half.
If you required 3 Aerial Blasts to kill the sheep Aeyela my only thought would be you may not have had an ideal atma set up and/or gear.
I (and 3 other summoners) did Sheep in Abyssea - La Theine using Diamond Dust and they always went down in 2 uses of the ability. The pattern was simply Summoner:A Astral Flows > Diamond Dust > Summoner:B has their Shiva use Sleepga > 45~ish second wait > Diamond Dust = ~20+ kills.
I find though, that the best combination for using a summoner for trials is Summoner, Black Mage, and Red Mage.
Red Mage to pull, Black mage to ~aga the mobs so that only one Astral Flow Ability is required, for sleepga, and to build azure so that you will get ISL chests for the summoner to be able to Astral Flow repeatedly. Summoner to deal the killing blow and fulfill the kill requirement (assuming that it's perpetuation staves you're attempting to create).
-Side Note: Carbuncle with Searing Light is extremely useful for light damage kills for the few people who may attempt to make an Arka I.
This strategy obviously takes a lot more preparation and set up time to be effective so it's only worth doing in certain situations. But I find when it works, it works well.