Solution to Mudra lag, as an Australian Ninja:
-Press first mudra in the combo you wish to use.
-wait a a half second for Mudra buff to apepar on your effect bar.
-Press the next two Mudras as fast as you like.
-wait a half second for the effect to apply proper.
-Now you can Ninjutsu.

The total time is around 2 seconds. Less than a standard action, but not perfect by any means. This is how i get my Ninjutsu's to trigger perfectly, every time.