Never mind, you2. I just should think before I post something about replacing two lenses with one. 50 and 35: 1480 grams. 40: 1200 grams
One should not underestimate Sigma's value for physical fitness, but my shoulder, pulled down by nearly the same weight, has some other ideas... Gosh, this Sigma lenses soon will develop their own gravity field.
All your lenses have their own gravity.
https://spaceplace.nasa.gov/what-is-gravity/en/
I reckon solution would go in direction of antigravity field. Geordi, where are you hidding? ;-)