I don't have either of those recipes for sale, but you can get the Mighty Defender recipe for free by doing the mission Whipping and Mishandling (Rank 6-2), or by going to the 4 or 5 star Hall of Heroes and talking to Jorin (It costs 10,000 crowns). As for the Silversix recipe, you either find someone selling it or you can go search the Tier 3 Arcade levels and hope that Basil has it on sale when you reach the Depth 23 Clockworks Terminal (Like other 4 star recipes, it costs 10,000 crowns).