On espeleo i aigua you can read about the use of multimonty (“screwfix”), and more understandable, you can see two short videos about how to install them. It is interesting that the drill used here is Bosch Uneo, which weights just 1,1kg! These techniques are used in cave exploration in remote places, where the weight of the equipement is critical. (please note that this information is not enough to install a proper belay!!!) Another link to the same site for a previvious article on the same topics here.