Is there a faster way to write attributes?

I am trying to write custom attributes to lots of components inside a residential structural model (lots of different sizes - joists, beams etc) is there a way that I can copy custom attributes from one component and paste to another, rather than writing each attribute on each component in the model?

I think you may have hit one of the many shortcomings of DCs. They are very difficult to manage.

DCs are a real pain to work with, when the model is very complex and contains so many variants. I have been talking with someone with regards to a workaround using spreadsheets to control and copy the data, but have come to the opinion thats its not the right solution for us.

One extension (free) comes in mind:
Attribute Inspector.
You can very easily create your own dictionaries and apply them to multiple components ( or groups ):

and they also pop up in the 3D Viewer of Trimble Connect:

Is it possible to write a formula in the dictionary so it calculates (as a string)
ie. “=ceiling(lenx,300)/100”

You can write formulas as strings. But you need another extension that interprets them inside SketchUp. Take a closer look how DC handles it’s dictionary. Lot’s of xtra variables.