In theatre, I construct many custom lighting fixtures which (understandably) cannot be added into the Capture Library.  Therefore when creating plots, I mark the appropriate rig location with a Report Item.
Within a Report Item, it is possible to enter in a Patch, and Circuit number.  However these are never printed anywhere on the plot - this makes it difficult for Riggers to identify where a specific custom unit should be positioned.
It would be hugely beneficial to be able to also load in a Channel number, but key to this is to also make the resulting Report item's information printable on the Plot in exactly the same way as traditional fixtures.