You call them leagues but they are not, they are catagories competing in one league so why not actually split them up.
So if you are in enthusiast which should be any cooling above 0c, say you use a GTX580 which awards 49 hardware points, why cant the highest in that catagory be awarded max points for that piece of hardware so each catagory can get the max points available for a particular piece of hardware and make the spread of points better instead of the top 3, this would give an incetive to better your result, instead of thinking "that was crap, i gainned 0.7pts for the extra effort and moving up 6 places"
Obviously if you move up a league a recalculation at server level is required.
Also doing it this way you are truly competing in your own league and not against others from a higher league.