A. There are several registry settings that can be configured for PDC/BDC Synchronization :

These are all values under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Netlogon\Parameters

ChangeLogSize (REG_SZ) Default size for the Change Log. By default 64KB with a maximum of 4MB
Pulse This determines the gap in seconds between replication from the PDC to the BDC's. The lowest value is 60, and the max is 3600 (1 hour). The default is 300 (5 minutes). You may want to increase this time if the BDC's are over a slow WAN link.
PulseConcurrency The number of BDC's that the PDC sends pulses to concurrently. By default this is 10.
PulseMaximum The PDC performs a check that the BDC's are still there every so often. This is in seconds and once again the minimum is 60 and the maximum is 86,400.
Randomize The number of seconds a BDC waits after an announcement before answering. 1 by default.
ReplicationGovernor This is a percentage of the 128K blocks that are sent. If you had a slow link you may not want the PDC sending 128K blocks so you could change this to 25, meaning only 32K would be sent at a time. This will mean that the blocks are sent more frequently (25 would mean 4 times as often).
Update By default this is set to no, which means only changes are replicated. Setting this to Yes will cause everything to be replicated even if there is no change. This needs to be set on the import server.