All of this is fascinating. I recently asked a group of writers about getting things wrong in historical novels. You have to be a true expert to get everything right and there are not that many of them. Their answers were very reassuring. One person commented that he was taken to task because the true history he was writing was so far fetched! A good tip from another writer was to include the phrase 'My books are fiction set in history' on the copyright page. I have adopted this idea. Thanks to her.
Also on my copyright page I put the phrase Written in English (UK). I have never had a problem with people saying the spelling is wrong, thankfully. Perhaps this is the reason. I often speak in an American manner (a legacy of living in California) but I see no reason to adopt spellings or phrases that are unnatural to me. A woman did tell me that corn was not grown in Europe in Viking times. Oh yes it was! The word 'corn' in English is barley or rye or oats. American corn is maize which, I agree with her, was not in Europe at that time.
This is why I have been diffident about setting my books in America. I left there a long time ago and have only been back for short visits. I am not au fait with the opinions, or fashions or way of thinking of people in the US currently and there are excellent authors who are. I shall have to stick to the period I lived there, if I ever get around to writing an American novel. We'll see.