The lighter wheels are not necessarily better, depends on how you ride.
The heavy wheels give you a tad more inertia which can be useful, ie up the hill to the hairpin at Brands or the first left at Cadwell. OK they may take a little bit more braking as a result but this lends itself to smoother flowing riders as opposed to point and squirt methods.
Running twin discs has the same effect.
I swapped from heavy to light wheels and to be honest couldn't tell any difference (*maybe because I'm such a smooth corner demon
) so don't fret if you don't find a set.
*or just not good enough to tell them apart.