Every day, generate an archive of all the email you received. Encrypt it, sign it, and generate a hash. Put all the hashes on a public page. Write the procedur

Every day, generate an archive of all the email you received. Encrypt it, sign it, and generate a hash. Put all the hashes on a public page. Write the procedure up, and have a VP attest that they ordered this done and have audited a random sample to ensure that it was done to spec. Get the attestation notarized. Repeat once a quarter or so. If the VP moves on or dies, make sure the new VP is on board immediately. No need to have a screenshot, it's email. When a court requires you to show evidence, you bring in the VP, the notarized statement, a copy of the code, and the encrypted and unencrypted archive for that day.