Very WIP, but I wanted to get the very basic format down first. Anyway, here's a brief reasoning for including these sets:
The first two sets are basically the same as those in the original analysis. However, I've slashed Toxic with Toxic Spikes on the Support set, as it's quite a popular choice over Toxic Spikes in BW2 due to being much more reliable, and stall being much less relevant.
I've decided to remove the Offensive set for now, as I don't see why it would get used over Starmie in the current metagame. I've replaced it with an admittedly slightly weird set, but Tentacruel can function superbly as a spinner for sun teams that doubles as a check to rain teams - being able to abuse both the sun and rain. I've only included Toxic as sun teams will want the immediate Poison on things like Politoed, though I may slash Toxic Spikes with it. Notably, HP [Fire] allows it to easily 2HKO Ferrothorn in the sun, something it usually struggles to deal with outside of lucky Scald burns. Ice Beam is preferred over Toxic as otherwise you'll be begging for Dragons to come and set up all over you, though Protect could still be used to gain extra Leftovers recovery.
Obviously, these sets are far from final and I'm open to any and all feedback.