I quite often do tandoori chicken. Rule is, the hotter the oven the better. A proper tandoor is about twice the temperature of a normal oven, and they use metal skewers so the meat cooks from the inside out as well.
To check the drumsticks are ready, just stab them with a wooden skewer to make sure they are cooked to the bone, the sizzling juices should run clear. The marinade just dries out, and concentrates the spices.