When you add the oil doesn't matter for cooking as long as you let the total pan-oil system get up to temp before you add the food. Leidenfrost is used as a quick indicator that the empty pan is the right temp, but oil doesn't do a leidenfrost effect.
The advice to pre-heat the pan first is because if you forget an empty pan on the stove you get a hot pan, if you forget an oiled pan on the stove you get a grease fire.
Also try out carbon steel for a more nonstick type situation. Stainless is best when you want some sticking, like for building a fond for a pan sauce. Carbon naturally seasons similarly to cast iron, but much lower maintenance because you can wash it however you want and essentially rebuild the seasoning from scratch for each use.
The advice to pre-heat the pan first is because if you forget an empty pan on the stove you get a hot pan, if you forget an oiled pan on the stove you get a grease fire.
Also try out carbon steel for a more nonstick type situation. Stainless is best when you want some sticking, like for building a fond for a pan sauce. Carbon naturally seasons similarly to cast iron, but much lower maintenance because you can wash it however you want and essentially rebuild the seasoning from scratch for each use.