is there a way to set a timer to fire off at 00:00:00 forever (repeating the next time it is 00:00:00)

see /help /timer there is an example in the help file of kicking off a timer at a specific time.. use it and change time as needed for when you want it. Remember to read about arg for timer to say to use more than once (in this case arg will be 0 for that position)