If you really want a medal these are the easiest maps in my opinion. (All done as a 6 digit)
7star:airman or eternal blaze. 8star: hidamari no uta 9star: hidamari no uta or ascension to heaven.
7star:airman or eternal blaze. 8star: hidamari no uta 9star: hidamari no uta or ascension to heaven.