Use medium-hot, big, long peppers.
If the chilies are spicy, consider omitting the red chili powder from the chaat masala mix, besan coating, and onion mix.
Ensure the batter is not too thin, or it will not coat the chilies properly.
For crispier bajjis, add 1-2 tablespoons of rice flour and 1-2 teaspoons of oil to the batter.