>>53690737If you're minmaxing, you want a Slaking/Azumarill with Huge Power, or a Shedinja/Empoleon for Bug/Steel with Wonder Guard and Aqua Jet. Just fusing two strong attackers together doesn't get you that much except a bigger movepool.
Note that the stat calcs are:
>(2/3)xBody + (1/3)xHead for Atk, Def, and Spd>(2/3)xHead + (1/3)xBody for HP, Sp.Atk, and Sp.DefSo something like, Cloyster head Blissey body is going to have significantly worse stats than Blissey head Cloyster body... Although in this case, the typing is a lot worse.