The standard 1366x768 resolution can be snapped (split) to 1024x768 + 320x768, or the opposite. (the missing 22 pixels are the width of the grip). Snap is keyboard controlled with Win+. or Win+Shift+. (that's a period by the way). This is the only supported snap.
If your resolution varies, the ratios remains the same. SnapView, by the way differentiates Windows 8 from other tablets in that it allows for more than one mobile UI application to have active threads at one time.
My explanation: Windows is likely to support only snap for a long time, too. The reason I say that is from a development perspective, applications are required, in order to pass Store certification, to support full screen and snap layout. 50x50 layout would require yet another application requirement for developers to meet - and that would take a considerable reword for the apps in the store already and those pending and those nearing completion. 50x50 isn't currently supported. 50x50 won't like be supported anytime soon either.