Hello John,
I also have a production and a dev/test environment. I do the reload from prod into dev/test on a daily basis. I do not use the "-w -S 0" sequence on the slapadd in the dev/test environment. You are in a multimaster configuration, so using "-S 0" tells everyone that the entry was changed by someone else and that they need to sync up. (I admit I have not read that section of the code to be sure my belief is fact. Others may disagree with me)
My slapadd is simply:
slapadd -q -b dc=my,dc=domain -l production_ldap.ldif
~ Frank
I am not young enough to know everything. - Oscar Wilde (1854-1900)