Yawn - Well it does make the enemy consider switching, which is always good
Wish - I wouldn't recommend it for healing CAP8 itself 'cause it takes too long to work, but it is the only way to heal allies, so it's still a plus
Stockpile/Swallow/Spit Up - Stockpile makes CAP8 much harder to counter w/o phazing and the other moves don't work without it. Just skip all three of them.
Light Screen - Extra special attack resistance does help, especially with CAP8's lower special defense. However, I don't like facing off with both screens, so just stick with Light Screen
Reflect - see above
Cosmic Power - see Stockpile
Roost/Recover/Slack Off/Milk Drink/Softboiled - Recover's the only one of the lot that really makes sense, and they all do the same thing (except Roost, which removes the Flying-type part that CAP8 doesn't have), so really, stick with Recover. (RBG Edit: Don't choose just one, all or none)
Metal Burst - 80Spe is not slow enough to guarantee Metal Burst to work (50Spe would be better), 'cause it must act last since it doesn't have negative priority. Counter or Mirror Coat (or even both) would be better because they DO have negative priority, but not Metal Burst
Wish - I wouldn't recommend it for healing CAP8 itself 'cause it takes too long to work, but it is the only way to heal allies, so it's still a plus
Stockpile/Swallow/Spit Up - Stockpile makes CAP8 much harder to counter w/o phazing and the other moves don't work without it. Just skip all three of them.
Light Screen - Extra special attack resistance does help, especially with CAP8's lower special defense. However, I don't like facing off with both screens, so just stick with Light Screen
Reflect - see above
Cosmic Power - see Stockpile
Roost/Recover/Slack Off/Milk Drink/Softboiled - Recover's the only one of the lot that really makes sense, and they all do the same thing (except Roost, which removes the Flying-type part that CAP8 doesn't have), so really, stick with Recover. (RBG Edit: Don't choose just one, all or none)
Metal Burst - 80Spe is not slow enough to guarantee Metal Burst to work (50Spe would be better), 'cause it must act last since it doesn't have negative priority. Counter or Mirror Coat (or even both) would be better because they DO have negative priority, but not Metal Burst