Twin Spot Goby Help

[Enigma]

So, being a silly noob who clearly doesn't research her purchases well enough, I purchased a lone Twin Spot Goby a couple of weeks ago.

The store only had the one, so even though I learned that they should be kept in pairs very quickly after the purchase, there was no mate to go back and get. Should I consider looking for another lone Twin Spot? I'm not sure how to sex them.

This little guy is eating like a little piggie. I mix up a frozen mysis, brine, spirulina, and Garlic Guard concoction and inject it into the sand around his borrow. He clearly works the food in his mouth and his little belly noticeably rounds out. He looks good.

I am injecting a LOT of food into the sand (though this isn't being reflected in the tank's parameters . . . Thankfully!): probably 1-1.5 frozen cubes a day. What can I cut this back to?

Also, any ideas as to how I can deal with feeding him when I'm away on a week long vacation in August? I have an auto feeder for the fish that feed in the water column. They're not excited about pellets and flake, but they'll eat it. The auto feeder won't work for this guy, though.