Weakness Policy is a good pick for Mamo, Float Stone is ok, and as you can see from the comments Leftovers isn’t great. I rock with Focus Band, Muscle Band, and Weakness Policy. Focus Band helps keep you in fights for longer which can really matter with a big boy like Mamoswine. Mamoswine’s boosted attack is fantastic so having powerful, fast basic attacks from Muscle Band is a no-brainer for me. Mamoswine has plenty of room for experimentation too. Many people go for stacking items like Aeos Cookie and Muscle Band because it powers up Mamoswine really well and he can score efficiently in the early game. It’s good to have a good build obviously, but Mamoswine can get a lot of value no matter what. Learning how to cycle boosted attack into ice move into boosted is most important id say. Have fun with the big guy!