went to the shop today, tried both the S and M sized cartels.
On the S sized ones the heel overhang and the toe overhang seems to be more or less the same.
But the ankle straps were too short and they had to be adjusted to the longest length to surround the ankles. Yet it looked flimsy and may break soon.
On the M sized ones the toe overhang would only be around 1cm while the heel overhang is around an inch.
If the transparent bubble on the binding fits precisely into the rail which is the middle of the board, then the heel overhang would definitely be larger.
So which size should i get?
you don't have to put the bubble in the centre, you can adjust the bindings so that the overhang is equal. Also note that you can probably make the toe part of the binding shorter or longer, at least on some burton bindings if not all.
Sounds like you should get the medium so the ankle straps are the right length.
lastly I hate all you guys with your deep powder and your cheetah's, I so wish I lived somewhere that I had good reason to have a cheetah instead of riding the white ribbon of death unless I get on a plane