I will need help testing.
Let me first release a new version of IXCoin with just the OP_RETURN changes. Then we can test this version against the modified counterparty client.
I assume the update will be based on version 0.8.6, not 0.9.0, which is ok.
What about native IXC escrow? I still think that would be best for the reasons already stated, even if it takes more time. Maybe we should vote on IXC escrow.