Pokemon that are "outstanding" or "relatively superior" are pretty good - it refers to the

sum of all their IVs. Outstanding or superior Pokemon are much better IV-wise than those that are "above average" or "decent."

The Macho Brace doubles the amount of EVs you get from beating a Pokemon. Basculin normally gives 2 Speed EVs, so when you beat one while using the Macho Brace, you get 4 Speed EVs. So you would need to beat 252/4 = 63 of them to max out Speed. Litwick/Elgyem both give 1 Special Attack EV, so with the Macho Brace they give 2, which means you have to beat 52/2 = 26 of them. Audino and Stunfisk give 2 HP EVs (Ducklett only give one, so I wouldn't use it), which would be 4 with the Macho Brace meaning that you have to beat 204/4 = 51 of them.

Of course, you can make the whole EV training process faster by giving your Pokemon Vitamins. You can give a Pokemon a max of 10 Vitamins in any stat, for a total of 100 EVs in that stat. So if you gave your Pokemon 10 Carbos, 10 HP up, and 5 Calcium, you would only have 152 Speed EVs, 104 HP EVs, and 2 Special Attack EVs to get from wild Pokemon.

Also, using

Power Items is better than using the Macho Brace. A power item will give you an extra 4 EVs in a certain stat after you beat a Pokemon. So if you give your Pokemon a Power Weight and beat a Stunfisk, you would get 2 + 4 = 6 HP EVs.

Getting the Pokerus will also double the amount of EVs you gain from battle.