I hugely prefer 12-3/12-5 + SG for a couple of reasons:

1: 12-? is currently the only way to get Ampys, where your need for Manyu's at one point will stop, you'll always need Ampy's. (well 'need' is a strong word, but it will be your only way to get stronger at some point). Why cripple yourself now by reducing the amount of Ampy's you can get?
2: 12-3 and 12-5 give gold and exp. I find them more stamina efficient.
3: WHY CAN THE 80 STAMINA DAILY DROP FREAKING LEVEL 5 MANYUS? (capslock rage off). If I do the dailies I get 1-2 level 5 Manyu's at the very LEAST. This is my biggest problem with the daily, RNG. You can miss chests by sheer bad luck and you can get level 5 Manyu's making it an incredible waste of 80 stamina. Atleast the advanced SG has guaranteed 20+ Manyu's..