For us it helped when we put one DPS + healer on one tentacle and other 2 DPS on the tentacle. They will be slightly out of sync but DPS uptime is better as the buff tentacles get makes uptime very low on second tentacle being killed. Also this will keep the DPS on anomalies a bit more busy.
but they go down the same if not slower that way. The longer it takes to get to 30% then longer it takes to use execution moves.