Hopefully my experience will be helpful here as I couldn't find a lot of posts from people who had been through this exact scenario when I was driving myself crazy.
I went for my I-130 spouse visa interview today in London and was in a similar situation (incorrectly answered no to the arrests/convictions question with a minor arrest resulting in a caution on my record from 12 years ago for abusive language).
I brought it up as early as I could at the embassy (I also had copy of my subject access request and printed correspondence with NVC to ask if I could amend my form when I had realised my mistake, to which they said raise it at interview).
I was only asked for the SAR at the first window, and they didn't need to see my correspondence with NVC. I again brought it up proactively at the second window - the officer asked me to explain the situation, I gave a v. high level summary of what had happened and when (in my case it was almost 12 years ago) and the outcome - he told me this would not be a problem.
Majority of the questions were about when / where I met my wife, and our situation now - I was approved on the day, and told that I will receive my passport back with the visa within 2 working weeks - the whole interview only took about 5 minutes after waiting to be called to the window.
I really hope anyone who (like me) has been worrying about a mistake on their form for the past 18 months - will see this and find it helpful. My advice would be to bring any concerns / errors up yourself if you know of them as the officers will appreciate you being upfront.
Obviously this is just my experience, but I will say that everyone I spoke to at the embassy was super helpful and friendly, and i'm convinced they are not in the business of declining applications unless they have to.
Good luck everyone!