Recommended Exchange 2010 SCL Settings

Have an issue with too many legitimate e-mails being rejected by our single Exchange 2010 server.  I recently modified my settings, by increasing the DeleteThreshold from 7 to 9, but not sure if that's enough.  These are my settings, any advice on how I can improve?  Ideally, I would not want to have e-mail completely rejected, instead go to the the outlook users Junk E-mail folder, or get quarantined for later retrieval.  Several users report they aren't getting any Junk E-mail, and fear they are not receiving legitimate e-mails.

Name                                  : ContentFilterConfig
RejectionResponse                     : Message rejected as spam by Content Filtering.
OutlookEmailPostmarkValidationEnabled : True
BypassedRecipients                    : {}
QuarantineMailbox                     : junkmail@company.org
SCLRejectThreshold                    : 8
SCLRejectEnabled                      : True
SCLDeleteThreshold                    : 9
SCLDeleteEnabled                      : True
SCLQuarantineThreshold                : 7
SCLQuarantineEnabled                  : True
BypassedSenders                       : {}
BypassedSenderDomains                 : {}
Enabled                               : True
ExternalMailEnabled                   : True
InternalMailEnabled                   : False