HW
Dry footprint means you can suffer a depressurization, descent to FL 100 and return to the west coast OR continue to an Hawaiian airport. Hilo is the closest on most tracks, but there isn't a whole lot of difference--80-100 nm. Wet footprint means there is a band in the middle that will mean swim time UNLESS you limit your descent to something above FL 100 and have sufficient oxygen to suck on a hose. FAR 121 and 135 require a dry footprint.
Your flight planner should be able to add ETPs for both the OEI and depressurization cases. I hope you have been to an international procedures course because I don't want to explain ETPs here.
GF