You have got the weights confused. The Contemporary is just under 2kg, but the Sports, the one they are now producing for mirrorless as it says in the OP, is 3.155 kg working weight. The 60-600 Sports is actually 0.3 kg less. As for the 100-500mm, it’s the best telephoto zoom I have owned, and nearly indistinguishshable in sharpness and weight from my very sharp 500mm PF, a lens you describe as sublime. The 200-600mm that you like is 2.4 kg, only 0.4kg lighter than the 60-600mm at that you have written off as being too heavy and 0.8kg heavier than the 100-500mm.