Glad you like it. I really think we're on the right track with it - I was surprised the linked article didn't come up with the same idea.
I don't see much point in an even distribution in radial distance from the centre. If you want to model something like the distance from the bullseye to an archer's arrows, you're presumably going to want a normal distribution on radial distance from centre, which is of course very different (though at a glance they might look similar).
