I think the trouble here is that the people who best understand cast iron are probably also the least likely to care about the science of it.
The main reason not to leave too much oil in the pan is that it will go rancid and get sticky and generally gross. That's not something you run up against if you use the pan several times a week, but if you have something like a dutch oven that you use maybe once or twice a month, you will come back to a mess that you have to deal with before you can cook in it.
The whole "you're making a polymer coating that mimics a teflon pan" idea is something that sounds fancy, but is impractical and unnecessary in practice.
Hmm. Perhaps. I said science-based information because while I find the science (chemistry, polymerization, etc) of cast iron interesting, I primarily care about the results. For example, knowing that flax oil gives the non-stickiest finish but is prone to flaking and thus high maintenance. Perhaps empirical would have been a better word than science-based. I suspect there are a fair number of people like me, who would like to know more about the trade-offs involved in different oils and maintenance procedures. But perhaps these aren't the people who best understand cast iron, as you say.
Two things of note:
- The best answer in the FAQ in the top comment of this thread, by FAR, is #2, about heat spreading. It gives numbers and additional information (about radiating the heat) that I didn't know before.
- Flax is the only oil that I understand even some of the trade-offs of using. That is a direct result of the post linked in this thread publicly making a hypothesis and providing detailed-enough steps for (some people) to reproduce its results.
Speaking of, as a cast iron enthusiast, would you be willing to share your experiences and/or do some experiments to help test my hypothesis on cleaning methods, here? https://news.ycombinator.com/item?id=25716850
I have a cast iron and a carbon steel skillet. I will always reach for the cast iron to sear a steak, but the carbon steel skillet gets used for pretty much everything else.
edit: I discovered cast iron about a year ago and now I do roughly 90% of my cooking on it. If there were reliable, science-based information about how to care for the pan best, it would have saved me a lot of trouble. As an example, a lot of people caution against seasoning with too much oil. They say that when you season your pan (e.g. initially, in the oven), you should wipe the oil off until the pan looks dry. I took this literally, and wiped until it looked the same as before I put on the oil. As a result, my seasoning had approximately no effect. After experimenting, I've decided that the "looks dry" advice isn't wrong exactly, but "dry" needs clarification. It should look more like how you would like it to look when it comes out of the oven — dry, but darker and with more sheen.