After about 3 weeks of trying, I finally cleared and farmed A8s with a PUG and 3 semi-static players. Of all the raids I've done so far, A8S Burden of the Son Savage is hell. You can die instantly or wipe if you don't meet the DPS checks or do the mechanics wrong.
It takes fight knowledge and teamwork to get it done over and over again to successfully farm it like how we did. Patience was also a vital key since it's a different mix of players. It's a challenge itself to get the group filled up in party finder. But the long wait was worth it and the several wipes we endured to finally figure it out.
To anyone who wants to farm it, be patient and open to try ways to clear it. I can only blog what worked for me and the group - but yours will be different and the players you meet as well.
That said, here's how we did it.
Average item level was 330 and up. All Level 70 players.
We burned Onslaught, Blaster, and Swindler. We killed Vortexer and Brawler at the same time.
We survived the chakrams, the robot tethers, and the flash.
Chakrams are like shurikens than spawn randomly along the edges. Make sure you do not get hit by these while tethered to a bot.
Robot tethers will attach to players who get marked by a purple icon. You have 3 seconds to look at robot arms while you are safely away from the Chakrams. Arms up, look away. Arms down, face robot.
You have a 3 seconds to hide right after surviving the chakrams and the robot tethers. Go to the center Robot and hide behind any of it's legs. Make sure you are not merged with leg. The flash always comes from west by the way, so make sure you check if your character will be exposed.
Doing these mechs the wrong way are instant wipe or death.
Tanks and DPS must live. Only healer with number stack may die at that point. Tank with number stack will go all the way to East, using line of sight to dodge the flash. The flash can be survived as long as your character is hidden behind a leg, no matter how close or far you are.
After the flash, Brute Justice will cast debuffs that is similar to weakness. So if you died before the flash, your weakness debuff will stack together with Brute Justice's. your dps will surely fall down and there won't be enough time to compensate.
After Brute Justice spawns 2 orbs at East and West. 2 players must kill them for additional 10 seconds and burn Brute Justice before he casts Gavel. Note that once a llayer engaged with the orb, the rest of the party must not help. Helping with orb will explode and wipe the team.
Failing to kill before Gavel will result to a wipe.
We took food boosts to compensate the debuffs and add up to our damage.
A lot of those clears were hanging by a cliff. But it's better than doing Gavel and increasing possibility of latter failure.