If you're low level, then you'll be running duo top still since most folks can't handle 2v1 or the jungle at that range.
Since that leaves you at blind pick, you've got plenty of options. You can go the hard to kill route, like a vi/garen top, or you can supplement eachother's weaknesses and have your friend run a solid ranged setup - but I would suggest focusing on going with someone tanky since at least one of you will probably end up in the tank role.
Singed wouldn't be bad, as his poison and mobility make him hard to kill yet at the same time deadly for your opponent if they pursue too long.
Blitz could work if you can get the skillshot down.
But basically since your games won't be following the current meta, its pretty up in the air for you.