Well, it seems like either day, you are gone for 12 hrs, which is pretty much, most peoples schedule, that work.
I feed them at 6am, when I get up for work, and around 6pm, when I get home from work. On a day, I can sleep in, they start bugging me, around 8am. They walk on me, and meow, meow, meow. Then Bump, all 20 lbs of him, lays on my head, and pulls my hair, with his teeth. That one, always gets mommy up, m-o-l.
Is it possible, to have someone come in, like mid day, to feed him? I understand if its not, money wise, it was just a thought.
Or if it upsets him, maybe when you get home, feed him 1/2 of his portion, then the other 1/2 in an hour?
Only other things I could think of. But Lola's suggestion, of doing a test run, with the feeder, might be your best bet. I have no experience with feeders. The kittens would turn it into a toy, and figure out, how to get it open, the same kittens, who can open, any, trash can. Or Bump would show them, how to set the clock ahead, so it opens early, m-o-l.