Laji, a good way to know is by simply keeping an eye on your profile, the time count down for sign ups will be displayed there. Other than that, you can google what time it is for pst, and compare it to your time to work it out.
Hmm, I think there is a easy way to deal with inactives at war, just remove the prize if no whatsoever contribution was given, just like parties, those who hit zero gets zero.