I was curious what the most important component was that determines what Adsense ads are shown on pages. I've heard that the file name and the keywords/phrases in the filename have a pretty significant impact on what ads are shown, but does Google spider the entire page as well to help determine relevant ads?
I am not sure how relevant this will be to your question however some people who visit your post might find this helpful... They offer auto ads as of February 2018, so now you do not have to worry about optimizating the placement. They even learn your site enough to show the ads at optimum times for peak income. They even place the ads for you within your site after placing just one block of code with the <head> tag of the pages you want to show the advertisements.
They cater ads to that person based on their prior searches, especially their prior searches regarding products online.