Thanks guys, I think the best usage of the stipend will be to get the economy comfort tickets. But since there's 2 of us (me and my wife), I didn't actually want to spend extra money, so I'll buy for the LAX --> OGG direction Economy Comfort, and also buy an extra 3k bonus miles for $59 one way. The total will be $217, of which $200 ought to be reimbursed by Amex.
So, for $17 on my part, I will be getting -
2x EC seats (going only)
bonus 3k miles
I'm comfortable with that.
Thanks again!