just to check edd, is it correct that with normal steam games, the mac developer only gets anything, and it only gets registered as a mac game, if its first run on a mac?
ideally i try to do this, even if sometimes i then later play the pc version, but sometimes it comes out pc only first, i play it and later a mac version appears on steam.
It works a bit like this:
If you buy it and only play on the Mac for the first month then it is a Mac sale.
If you buy it and only play on the PC it is a PC sale.
If you do both it is shared revenue based on game time (I think).
Edwin