How much easier is it to recognize other duals once you have had a dual relationship?
I can spot ESTj fairly well I guess, they usually have a more masculine appearance, they laugh at their own stupid jokes, and they oftentimes wait for confirmation when they make statements as if they are nodding whenever they say something relevant. Also their Te is pretty evident, maybe ESTjs are among the easiest types to spot.
The general question is, once you are 100% sure you have found a dual, how easily can you spot other duals?