Hi Ryan and welcome to battlezone!
I live in the UK (GMT) and I find that battlezone starts becoming more busy from around 7pm and onwards into the early hours of the morning.
I think Sweden is 1 or 2 hours forward from GMT so I'm guessing that the best time for you to come on battlezone would be 8pm or 9pm until about 4 or 5 in the morning? If you would be up that late! (or early!)
But on occasions there are games on battlezone at random times of the day, so it is best to check the lobby (or lobbysit, which is literally just to stay in the lobby for a while) in order to see if there are any games in progress or if anyone wouldn't mind playing a game with you.
Joseph.