I have left my fish go without food for 8 days and they were fine. I had someone come in daily to check the tanks but I didn't want them to be overfed so I told the friend NO FOOD, No food is better than a tank that is overfed.
the quality of the feeder doesn't really matter if you get used to using it. if you're not going to take the time to get used to them the only thing you can really do is get one with individual reservoirs for each feed.