>>30237925>>30238077It took me 31 beast balls to get Smeargle, who has a catch rate of 45. So you will need to stock up insanely if you want to do something with a low catch rate. It's time consuming to get the one ball at the time, but worth it.
I'd recommend doing a utility pokemon though. A syncher (can be any nature, since the sync is determined by the first nature in the party as long as the sync pokemon is on the field for SOS chaining... Weird glitch), a cute charmer, a pick up slave, a catch slave, etc.
I did smeargle first as a catching slave. I picked beast ball because the animation is very rainbowy, and I didn't have much faith I'd get it in the single level ball/fast ball the game provided for me. Just make sure false swipe first before killing the non-shiny smeargle, because if it misses sketch, it'll suicide fast. (False swipe also has 40 PP, so it'll save your ass for 40 rounds. After that, smearlge will struggle to death.)