Look at the old documents and Modern substitutes for Rodinal on here.

There needs to be excess for the hydrolysis to occur iirc. What you could do is add a small amount of sodium sulphite instead, after a few drops, drop in acid slowly to neutralise the hydroxide as that should be the solvent for the 4-aminophenol, filter it out, dry and weigh it, make up a solution with that and sodium sulphite and just enough KOH or NaOH?