thanks man, i posted in tech, but got no replies, looks like im gonna order a 41 tooth, since they only list up to 4.88s, im assuming im going the right direction
Without looking, I cannot say for sure, but it seems there is a section in his article that has an equation for determining exactly how many tooth sprocket is needed based upon tire size and gear ratio.
Of course, that is only as good as what sprocket size is available.