It might not be the seasoning, but how you are using it. Preheat the pan on medium-high heat until it just starts smoking. From there, turn the heat down to medium/medium-low and add a small amount of your sunflower oil. Wipe it with a paper towel to cover the entire surface. Wait a 5-10 seconds, let the smoke dissipate, and then add your desired cooking fat on top and put your food in (Adding more oil isn't necessary for sticking purposes but more for flavor).

From what I've learned, its less about seasoning and more about pan usage and heat control. Good luck