I've been at this for 50 years and I still struggle to understand things. But if you go into the big box store and the clerk reads you something off a product label, that's now expert opinion.Do you go to the big box stores in Civil War history (McPherson, Davis, Gallagher, etc.)? They have tiny labels on their products that solve all sorts of Civil War problems. Is that where your "expert opinion" is coming from?
Gardening is harder than that.