Most Important SS' to read from CFAI all, important, relevant, survey

iteracom

so a quick survey, what are the most important SS’ to be read from CFAI? this info would be relevant for all those using 3rd party providers
looking at EOC qs, im thinknig books 1, 2, 3, and 6 should be read from CFAI but a 3rd paryt is fine for books 4 and 5.