If you need to feed slimes after the split, you're in full i55 gear or playing with bad players (which is likely, because 99% of you can't even DPS correctly).

We were one of the first groups to down T1, in a mixture of i55 and i70, and we only fed slimes until they split. After split, we stopped feeding and rotated cooldowns on the tank.
Burn down one snake, limit break the other, and then kite it around in circles until you win.
It's very possible (and easy) without excessive gear.