Rice brain oil is a high smoking point neutral oil, which is great for making chili oil and stir fried dishes. I hope you enjoy cooking with the new ingredients!

Yes, you can use gochugaru. Chinese chili flakes is a tide spicier than gochugaru, but not by a lot. The chili oil should be very fragrant and not super spicy, so you can use quite a lot in a dish without making it too hot (Sichuan cooking usually requires extra chili pepper to add spiciness, on top of the chili oil). That being said, you can add a small amount of cayenne pepper to the gochugaru if you wish the chili oil is a bit spicier.

The Chinese chili flakes are the best ones to use (like this one). But if you cannot source Chinese chili flakes, I feel like Korean type is the next best option. Chinese chili flakes are not very spicy either. The oil is more fragrant than hot. And you can use quite a lot in a recipe without making a dish too spicy. If you want a slightly spicier chili oil, you can always experiment with using gochugaru plus a small amount (like 1/2 to 1 teaspoon) cayenne pepper.

I wouldn’t use olive oil because it has a very strong taste itself. Any neutral oil will work much better in this recipe than olive oil.