30 minutes fuel. I thought that was pretty standard.
As an aside, do people actually declare on freq that they are 'committing to stay' or commit to destination? - I have never ever heard it said, but many many arrivals into eg LHR must do it from time to time (ie burn the diversion fuel whilst holding to land at the destination) [2 independant r/ws yadda yadda].
Unfortunately my current ops manual makes no provision for committing, so I must divert when I reach div+reserve, even if the div field looks less certain than the destination.