Just to point things out, Shell Smash Crustle should run Jolly. Adamant is tempting, but it's bad because after a Shell Smash, Adamant Crustle will hit 378 Speed, meaning it will be outsped by some Scarf users. Custap Berry Crustle also doesn't run bulk investment on purpose in order to activate the Custap Berry sooner.
While it seems tempting to use Rocky Helmet on Weezing, the passive recovery from Black Sludge is much more helpful in the long run, as Pain Split can be unreliable at times.