Meta Lock AE Macro - Possible?

Can't test this right now, but trying to work out a way in a single, mashable macro to use two different AE options based on the stance status of my lock who has the Metamorphosis talent. When Meta is up, use the awesome immolation aura. If meta isn't up, target my main's target and case Seed of Corruption followed by a Rain of Fire. In checking wowwiki previously, the meta stance is stance "2", so would this work? (Also, I use an assist system to get my DPS targeting a specific mob. In this case, I want to keep that as their target and use potentially a new target (whatever my main is targeting) for the SoC cast.)

Code:

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/castsequence [target=party1target,nostance] Seed of Corruption, Rain of Fire; [stance:2] Immolation Aura

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The rain of fire will not be spamable because it is (iirc) a ground targeted spell. Also, IA is a channeled spell, correct?

For a multiclass team I would simplify it to:

/cast [target=party1target,nostance] Seed of Corruption; [stance:2,nochanneling] Immolation Aura

I can't comment on the stance issue.