I'm on 300k and I start thinking twice if it's over 20mb. The biggest bits tend to be music as 2 or 3 tunes will probably be 10mb or so. I would suggest making your game run with or without music and either have a music + game download and game download or a game download and an add music patch download. This way people can download the 20mb of game and if they want music they can download the additional xx mb if they want.