Unfortunately, they do contradict each other sometimes. GLs should be studied well. This is where you find the compliance or specific purchase requirements. Banks have pics of mandatory docs, whether to go to a teller or an FCR, what you should disclose, what you must wait to be asked. Gas station GLs have an astonishing amount of detail. You have to know requirements for a Mid-sign, bollard, and canopy. Many shops want to know if a promo, discount or ad is current and displayed correctly.
That being said, You definitely want to read the eval (ideally print and take it with you) BEFORE the shop. There is regularly a specific 'objection', 'statement' or 'question' necessary to complete the shop. At the end of the day, if you can't answer the questions you cant submit the shop.
As far as contacting your scheduling, you can call if you want but I would definitely email, too. You can send a couple of emails on the first day with your question or concerns and say you'll be waiting for a reply. After that, once each morning to 'touch base again about job #____. If you don't get an answer, it's on them.