I went for the relatively easy Lightness Sorting.
I built an array of my hex colors, sent them through this cycle, then sorted them by sum value.
$r = hexdec(substr($color,1,2));
$g = hexdec(substr($color,3,2));
$b = hexdec(substr($color,5,2));
$average = round(($r+$g+$b)/3,0);
$min = min($r, $g, $b);
$max = max($r, $g, $b);
$sum = $average + $max + $min;
At the moment I don’t have much time to fiddle with this, but might worth to try and build a two-dimensional matrix based on the HSV Sorting. That looked pretty cool. One just have to position the color higher or lower on the y axis according to its lightness.