Brought in the Sanhedria Murchevet weekly Torah newsletter: the minhag is to add something choshuv to the Shabbos seudah lechvod Rosh Chodesh. Some say too davka have a large meal for Melaveh Malkah, but some say that isn't either nikkur, and so, one should have a seudas R"C on Sunday.
Looking for a mekor for the chumrah to eat a seudas Rosh Chodesh on Sunday when R"C falls out on Shabbos, so that it would be obvious that the seudah is for the sake of R"C. I desperately need this mekor in the next three hours.