How free are we to add the suffix -iĝ- to a word when we want to give the idea that we or someone or something is becoming the thing that the word concerns? I'm not sure how else to ask the question.
An example of where I've seen something like this would be Kial mi Esperantistiĝis for Why I became an Esperantist.
Here are some other example sentences:
I want to become a cameraman: Mi deziras kameraistiĝi (instead of Mi deziras fariĝi kameraisto).
Ice becomes water: Glacio akviĝas (instead of Glacio fariĝas akvo).
I came to this question when I was trying to think about how to translate the following sentence, which has a little different structure than the above examples.
I was only joking about becoming an actor. Mi nur ŝercis pri ____________________.
How should the blank be filled in?