The {@playerlist@}
token needs some kind of “condensing” features. It doesn’t make sense to list each one of your 6 horn players in a different line. I’d say that you could condense players like you do in the staff labels (e.g. “Horns in F 1.2.3.4.5.6”) if the players hold the same instrument and have no auxiliaries. Another alternative you can see frequently is to condense them to “6 Horns in F”, but the current logic for staff labels is good enough in my opinion.
This is just one of the many features you would need to implement to have really good, standard instrumentation list, but I think this one would already get a pretty decent one without lots of complications.