As it says in my sig, I'm not quite at that level yet, but I believe it's been mentioned that the Helix spells last around 5-6 ticks of damage, at 9 seconds per tick, that's around a 1 minute duration, and of course Modus Veritas cuts it in half.
Against Gods and stuff I believe that the helix damage gets severely resisted, to the point of getting "zeroed out" against something like Kirin.
If someone who's actually tested these could confirm or correct me, that'd be great.
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~~ Puppetmaster // Scholar // Thief // Dancer // Blue Mage // Corsair // Geomancer // Ninja // Ranger // Summoner ~~