OptiX 8.1 added a function called optixGetGASPointerFromHandle() that can be used to help index per-instance data, rather than making per-instance SBT entries. Since this removes an entire dimension of complexity with SBT size, creation, and management, it can not only simplify OptiX applications, it can in some cases make them faster if the SBT has become very large.
We are updating our general SBT recommendations to include keeping per-instance data separate from the SBT and to not create an SBT entry for each instance. Recently Keith wrote a great article detailing how to do this.