I would like to suggest adding the ability to hold shift while pressing "C" to mass select controlling objects to link to a slave object("V"). Kinda adding in the reverse effect to being able to mass select with "v+shift"
I came upon this while using the new(er) load/unload rails. The wiki page promotes being able to link many of them to a single storage for cargo transfer while objects are moving on a rail. I was selecting unload rails and had to select each one individually to master it to storages in order to make a moving cargo unload rail for a project station. Setting up a sequence of master unload rails to send to a single storage slave so cargo pods could travel while unloading is extremely tedious. Being able to select masters en mass would be a huge benefit to the newer rail blocks and how they have to be linked to work with storages, IMO.
I came upon this while using the new(er) load/unload rails. The wiki page promotes being able to link many of them to a single storage for cargo transfer while objects are moving on a rail. I was selecting unload rails and had to select each one individually to master it to storages in order to make a moving cargo unload rail for a project station. Setting up a sequence of master unload rails to send to a single storage slave so cargo pods could travel while unloading is extremely tedious. Being able to select masters en mass would be a huge benefit to the newer rail blocks and how they have to be linked to work with storages, IMO.