OK well my friend adn i were having an argument about EVs. So i came here to clarify if im right or not.I'll just put it in a a real life situation to explain easier.

I want to train a level 50 metagross with this moveset

Metagross
-Meteor Mash
-E-quake
-Psychic
-Sludge Bomb
252 EVs in Attack, 252 EVs in Sp. Attack and 6 in HP.

Ok so when i get beldum i give it 5 protiens to raise its attack by 50 EVs. So that means i have 205 Evs in attack left.Then i battle 205 trapinches so increase its EVs.

Also after giving the EVs to beldum it is only at level 35.So does that mean i can give rare candies to him since i have the maximum EVs i can get.

Tell me if im right or wrong.

P.S. Feel free to change what EVs i should give him and any moves i should remove/add