on *:input:*:{
  if ($1 == - || $1 == +) {
    if ($mid($1,2,1) isin $nickmode && $2 ison $chan && !$3) $chan mode $chan $1-
    elseif ($mid($1,2,1) isin $chanmodes && $2 !ison $chan && !$4) mode $chan $1-2
  }
}

there we go