Hi Keith. If Message Sniffer is set to 30, that means it will add 30 points to the overall score of the message if it is triggered. So basically, if you have your delete weight set to 8, messages that trigger Sniffer for 30 points will be deleted because it breaks the threshold of 8. Since Message Sniffer has very few if no false-positives, it would be fine to leave it at a high weight such as 20 or 30. Just a comment... Your spam setting seem extremely strict in my opinion. In my experience (and I look at about 20 servers per week), most folks have the following settings:

 

Spam Low: 10 - Take No Action

Spam Medium - 14 - Move to Junk

Spam High - 20 or 30 - Delete

 

Any reason why your settings are so strict? If it's because you are getting a large amount of spam, I will be happy to offer suggestions and share configurations that work for me and our customers. Again, in my experience, having very strict antispam settings can cause a lot of false-positives which can be just as bad as too much spam. I hope some of this info helps. Thanks!