I have seen this used with other words besides "large" and "small". What other words can be used? Can this structure be used more generally with other adjectives?
"Writ" as a verb is an archaic form of "written", the past tense and past participle of "write".
Hence it will take any adverb that applies to writing.
"Writ quickly", "writ slowly", "writ convincingly", "writ badly", etc.
However, I don't recommend using it, except for the idiom "writ large".