Eheim auto feeder worked well for me.
I think the size of the food, the type of food, and feeding frequency is what's important. It also depends on your livestock needs as well.
When I had mine up and running I mixed NLS pellets, Spirulina pellets, Ocean Nutrition flakes, and some kind of Formula 1 pellets all together in the feeder. I set the food dispenser opening on the smallest possible setting and used a piece of duck tape to secure the slider opening in place. I've read too many stories of the food dispenser opening wider on its own and dumping all the food in the tank...don't want that to happen.
The one I had can be programed to feed 4 times a day and can be programmed to rotate once or twice for each feeding. I only had it programed to feed once and rotate once. But depending on livestock and such a large tank as yours, you can program for multiple feeding and rotations.
Also, it's a good idea to start using the dispenser a few days before you leave. This way you can observe how much the fishes eat and how the food is dispense and make adjustments to the schedule or the feeder.
Sometimes the chamber on my eheim auto feeder don't rotate after I touch it, so I usually have to coax it a bit, but after I do it works normally, at least until I decide to mess with it again.