Dynamo script for rotating multiple elements (e.g Steel Column) around its center

Maybe not exactly an answer to your question, but if necessary you can always rotate a nested family within a loadable family too.
FamilyInstance.SetRotation might be more straightforward…
referentie roterend r station text as.rfa (1.5 MB)
Hilti ankers zetten + rotatie + naam+soort.dyn (149.6 KB)