if you are using a power trick shucke do not use a lonely nature. i would suggest impish for the best results.
the reason i do not suggest lonely is because it is +atk -sp. def.
shuckle is designed to take special hits and you dont want to limit its strengths. also shuckle's attack stat isnt worth increasing at all. you just need to make sure taht you have completely eliminated any physical attacker on your opponents team before breaking out the power trick.
other than that you seem pretty good