1. I trust anything, even vague, or slight that the church admits to. Like, in their site article on divining rods, they admit Oliver Cowdery had a divining rod, that it was in fact "the gift of Aaron" that one D&C section alluded to. So, when I find sources elsewhere that talk about him being a rodsman and money digger, it solidifies in my mind that this particular information is true.
2. Credentials are important. People like Dan Vogel and Grant Palmer, have long, respected careers as historians. Sandra Tanner and her husband have gotten access to a lot of old documents from church figures, same with Fawn Brodie. When these folks use the same sources, telling the same stories, it validates those stories. Like, the folk magic origins of Mormonism.
The CES letter brought up a lot of bulletpoint issues and I could sit and listen to Sandra Tanner or Dan Vogel talk about the actual historical context of Mormonism all day. But my aha moment? Came from reading church articles, the way they contradicted stuff I had been learning and taught IN church, in the temple, in general conference just in 2016-2018. And this sudden influx of apologetics that attempted to gaslight me, or attempted to get me to do mental gymnastics to follow along. I could feel it after, the way they were attempting to get me to contort.
Just as an example...there was no historical evidence of a Great Apostasy, you guys. There are no dates on the lds website. It's a vague, "Things got corrupted after the apostles all died." WHERE??? Where is the Mormon doctrine in any surviving documents?
I'd always understood that the 'great apostasy' occurred when the living apostles no longer choose replacements for vacancies, the group lost its identity, Christ withdraw his approval of them as a group of disciples...
Any evidence that meets my evidence criteria. Here are my criteria: When I ask to see the evidence with my own eyes, the answer will be "Of course sir, it's over here, you're welcome to look it over".
I rarely (if ever) want to look it over for myself. The important thing for me is that they would be happy to show me.