I use Kuoro Lucifer’s AutoHotkey script, and I love it. He’s got versions for 4 clients and 1080p and 9 clients at 720p. But you can use his scripts as a template for other setups (such as 4 clients at 720p for a 2560x1440 monitor).
Oh, and it has an extremely small overhead (only a couple of megs of RAM), which leaves as much system resources as possible for running your clients.