Hi, I have the same kind of feeder. I have a different set of animals though. I have 8 pygmy corys, 9 other corys, and 12 neon tetras, and 4 wrestling halfbeaks. I set the timer to drop as little food as possible and I set it to drop the food twice at around 8 pm which is an hour before I turn the lights out. I do this so the mid water fish get excited when the first drop happens, and then the corys come out, and the corys don't miss any food because the feeder drops in a little more. I've had one of these feeders on my tanks for about 3 years now because I work weird hours and I go to school, so I can't always be home. I've had no problems, but I will say that for the first week or so you should watch carefully how the fish react. About 2 years go I had a loach who was about 4 inches and he would steal everyone's food, so I had to set the feeder to feed him then about 15 mins later feed again. He'd be busy digging in the gravel and the other fish fed unmolested.
In my experience it takes a lot of observation and fine tweaking. You'll probably have to tweak it a few hundred times before you are satisfied.
Also, I usually take it off three days a week when I feed them live foods.
It can be a pain, but I like the auto feeder, because unlike me it never says, "well maybe they need more food today", and it never forgets or gets stuck at work or school.