In reply to riojaiv:
This isnt Bivacco Antigone, but a swiss bivak in the neighbouring valley (Cresta Biwak SAC). Bivacco Antigone is a really nice biwak, with wooden inside, table, panoramic big window, lights and usb.
Also i bivyed multiple times in the valley near saas-almagel, next to the road(that goes to mattmark) there is a nice picnic place with running water, and WC. And just above saas-fee just behind a big rock. Of course both times i wake up early as its illegal below 2k meters.
There are also some "rock-fence" type spots on lagginhorn (new) normal route around 3000m and in weismiess sse ridge route at the pass where the ridge starts. Near weismiess sse ridge but on the italian side there is a bivacco citta di varese. unfortunately i dont know the other side of the valley, but there is a biwak called Mischabeljoch biwak.