I would be VERY careful about using compression in the opt file.  When 
I used it on an NT client the backup times increased by a factor of 
about 10!  Obviously situations vary but I would check this parameter 
out in a carefully controlled test environment.  Compression uses CPU 
cycles and your active users would really prefer that these cycles 
were directed to running their office/business applications.

Murray Nicholas
IT Systems Consultant
Galeforce Information Services Pty Ltd
email:  murray AT galeforce.bu.aust DOT com