My original sentence was:
... an array of ...
However I decided I wanted to elaborate on this, as "(traditionally two-dimensional) array".
We usually use parentheses for extra detail not necessary to the sentence, that the reader could safely ignore. With that in mind, for which reader to I optimise 'an'/'a'?
... a (traditionally two-dimensional) array
or
... an (traditionally two-dimensional) array
My immediate thought was to 'work around' it - perhaps using 'original' instead of 'traditional', or taking the clause out of parentheses.
However even if I end up doing that for readability, I should be interested in your answers to what I consider to be quite a (interesting) predicament.