Thanks guys. So, how can I start to simulate cores in LTspice? Is there a way or should I not bother?

I wouldn't bother asking the AIs, just yet. They have a habit of completely misunderstanding SPICE syntax. I've never found them helpful.

You might consider looking the LTwiki. There is a chapter there on The Chan model, but there is plenty of meat in another chapter on Transformers, much of which is still useful for non-coupled inductors.

Please also don't forget that the group has a huge amount of experience from users that has been uploaded to files. If you just put "Chan model" in the search box, you get 34 hits, not all of which are directly pertinent, but many are. Check them out.

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Regards,
Tony