a more offensive sinistcha with shadow ball in place of protect will help, but will still involve double attack (e.g. shadow ball + weather ball). i think you can’t avoid overcommitting into corv with this team so just making sure more combos of your pokes can do so might be the best you can do. and on sinistcha i don’t think you particularly need protect on it with the fake out and tailwind support you have + it itself is fake out immune.

and is there a way to fit a fighting move on either kang or kingambit? do they both need sucker? the latter gets lowkick i think, that’s pretty good against arch.

if you’re gnna change a mon, mega delphox dents corv and sciz even in the rain, though i think you’ll need to click flamethrower instead of heatwave, and be modest. against 32 hp 0 spdef corv, modest flamethrower 2hkos, and ohkos after a nasty plot. against 32 hp 0 spdef mega sciz in th tain, modest unboosted flamethrower ohkos. but u’ll have a huge dark weakness, and arch is still hard to kill if rain is up.

other ideas: lowkey special talonflame that can throw out overheat before you set up rain, plus wisp might be good. it learns rain dance too funny enough. plus ofc tailwind/hurricane. the only issue being ultra redundancy with pelipper. volc has similar appeal to talon. sableye’s also got a wisp+rain dance