smeargle as a catcher pokemon.

i was going to go for jolly and then ev him for attack and speed.

but some discussions led me to believe that adamant and attack/hp would be better, because at some point in smeargles leveling the benefit from jolly and speed ev's wouldn't matter compared to the fastest wild pokemons, even the legendaries. how could I figure this out for sure?

I want to be as fast as possible to get a spore or false swipe off first everytime, be it legendary/friend safari, farming wilds etc.