This page summarizes some of the teams and their relative 'office hours', based on when they are normally online and available. These hours are of course not set in stone, but should give you some indication (beyond that of seeing them active) as to who might be around at a particular time of day to assist with any issues.
EU Timezones:
Becci
Absolver
Orange_Sheets
US Timezones:
AU Timezones:
EU Timezones:
Absolver
Xlexious
Adanaran
Marenthyu
US Timezones:
AU Timezones: