Unchained, when do I use it?

[Sylve]

So I understand as an off-tank you basically probably don't need to put up Storm's Eye (The damage debuff one), and can stick to the Storm's Path to help out Ninja, and BB for the most potency combo, throw in Fell Cleave etc when DPSing.

However as the main tank, in order to help my NIN friends, how do I keep up Storm's Eye and Storm's Path and use Butcher's Block without letting any of them fall off?

So long as I'm paying attention;
HS->Maim->Path
HS->SS->BB
HS->Maim->Eye
Rinse, repeat. Should catch the Path right after it falls off and the same with Eye when you get back to it.
20 second durations and roughly 7.5 seconds between each combo set, the whole thing takes about 22 seconds from start to finish. So the debuffs are both up almost all the time with about a second or 2 at teh most downtime.
Its not perfect, but it worked well enough for me through 2.x.