DCC newbie questions

We just installed DCC and hooked it to SA yesterday. It is working and we are getting DCC_CHECK hits. We understand it is basically scoring bulk mail, not necessarily spam. We see potential settings for dcc_body_max, dcc_fuz1_max, dcc_fuz2_max with a default/recommended 99. Are there

DATE_IN_FUTURE

We get email from international students from Indonesia, China, Korea, etc. Sometimes the email trips one of the DATE_IN_FUTURE rules. Does this happen because the sender's computer has bad date/time? Because of the time zone they are sending from? Or some other reason? Some of this email also

Snertsoft milters

We use milter-spamc with SA and sendmail. Snertsoft lists a number of other milters that could be used. I'm wondering which of those milters would actually add something to what SA already does and be useful to add to our system.

Rule to select sender starting with string

We are getting a lot of spam where the sender domain name changes, but the sender always starts with a specific string. We've only done a little bit of custom rule writing. How do we do a rule to get the sender starting with a specific string? Thanks, Al