Because a level 30 or above, 82% or above ralts is nearly impossible to find without some luck, you can try evolving it if they are not very common in your area. But you will be kinda dissappointed if it had a bad moveset.
Personally for me Ralts are not hard to find in cloudy weather, so i would just wait for a good iv, female one and evolve it and the males for gallade in the future.