[Zankou]

You have stated the correct .. you just grab the sleeve and go to quarter guard in that situation.

I like to try to armdrag that arm anyways as my number one option from z guard, so usually the opponent is either getting armdragged or trying to protect it. From z guard, here is what I am currently thinking in order:

Option 1: Can I armdrag the near arm?
Option 2: Can I grab the far foot for the foot grab sweep?
Option 3: Can I shuck his near arm over me and get a deep regular half guard?
Option 4: Can I kimura his far arm?
Option 5: Can I drive his far arm over me and dive into deep half guard?
Option 6: Can I reach under his far leg and grab his crossfacing arm, trapping it?
Option 7: Can I push the head and go for omoplata/triangle game?
Option 8: Can I kneebar the far leg?

That's my current set of "z guard" options. I'm sure there a lot of things I'll change, as I've only been focusing on this game for about two months.

Also one thing I find key for z guard is to use your "trapping" foot the exact same way Gustavo shows for the quarter guard -- angled down and always pulling in on the trapped ankle. That way he can't sprawl out. You can tweak his knee sidewise too if he does get the leg extended.