Caliper 2 SL
 
I Hyper tuned one of the arms just to see what I can get but the results were discouraging.  The strength analysis showed a low decrease in rigidity but the weight drop was also low, only 11 grams for that matter.  Most of these cutouts aren’t even doable and the weight still comes out to be an estimated 150 grams per caliper. 

Back to the drawing board.