I finished it! At last. It has been quite a struggle: some parts of this icon have been painted and repainted and totally changed 5 to 6 times.
Confession time: I had had some vague mercenary notions about what to do with this icon, and I suspect thinking about that interfered with the prayer journey. I was thinking about making greeting cards and small matted reproductions of this icon, and thus did not do any gilding on it. It is very difficult to photograph gold effectively, so this leaving-off-the-gold was planned from the start, in order to be commercial. I was thinking of The Guardian Angel icon as a product instead of a prayer. I forgot (temporarily) the purpose of writing an icon: to praise and glorify God, to witness to His Presence, to beautify His church, to bring people to prayer. Once I remembered that, and corrected my focus, things began to flow once more and it all pulled together.