Clamming & piles of commanders -- how about a different approach?

[Psycho]

I remember that you couldn't put two clams on a commander and generate two gems, but maybe that's changed. The F7 thing is useful only if you don't have any commanders in the same province with astral gems scripted to cast some battlefield spells. If you do, than it's risky using F7 because you can easily forget to give them gems back. But you can do the same thing with blood slaves, so why shift+z there?