The Spamassassin chronicles continue, now I know how to manually whitelist a single user or an entire domain of users. See below for the technique.
ManualWhitelist – Spamassassin Wiki
Whitelisting a user
Adding a user to your whitelist gives them a -100 score, which has the effect of always marking their mail as non-spam.
To manually whitelist a particular address, say email@example.com, edit your local user prefs file ~/.spamassassin/user_prefs:
# whitelist David Cary:
Whitelist and blacklist addresses are file-glob-style patterns, so firstname.lastname@example.org, *@isp.com, or *.domain.net will all work.
# whitelist everyone at sparkingwire.com: