While I haven't ever used them, I can't really recommend them... I think you're talking about the weekend feeders...? If you look at the nutritional content on those things, they're mostly filler. They're basically the potato chip of the fish snacks: fills your belly but little to no nutritional content. If I'm mistaken, then don't bother with this paragraph.
I agree with thominil. If possible, try to find someone to do it for you. Letting your fish go a couple days between feedings isn't going to kill them and will help keep down on waste during a time where you can't properly do a PWC