yeah I've assigned each of my dps to 2 platforms for irregularities. myself and the other tank do 14,16 and the healers get home and 4. I leave 12 as the leftover and have all the dps converge on 12 when they are done with their 2 assigned irregs
If you want to try and squeeze every little bit of DPS out, here's a suggestion about platform assignments...
Have a DPS assigned to 12+16.
That way you always have at a DPS start on a platform of an irregularity and end on one. So after the first set of tentacles are killed, you will already have a DPS on 16 (the safe 2nd phase platform) to start DPSing the tentacles as soon as they are up, and not running to try and get to them from elsewhere on the map.
Personally my group does the following. Tanks get 10 and 14 then move to 1 and 8 respectively. Two top DPS do 3,2 and 6,7 then move to 1 and 8 to help with the tanks (if necessary, either before their other 2 or after depending on where they are starting from 12 or 16). This can get a little hairy when spit goes out, but it's not really an issue once you have the internal clock for when spit is coming out again.
The other dps and healers split up 4,5,home. This should get you a little bit more uptime on the boss. Converging on 12 is probably a bit of loss as well, because you then still have to move everyone to 16 afterwards to start on the tentacles. Why have everyone converge on 12 when having 3 dps kill their irregularities and move to 16 to be ready for the 2nd set of tentacles and have the 4th dps just kill the irregularity on 12 then move to 16?