With regards to 500 000 bars limit - you can override this limit by adding following registry key
HKEY_CURRENT_USER\Software\TJP\Broker\Settings\MaximumNumberOfBars
enter DWORD value higher than 500000
Then adjust the database settings. Note however that such large amounts are rather recommended for 64-bit version of AB.
Note however that the default 500000 bars limit is only in regards to real-time plugins.
But i.e. data source: local database doesn't have a default bar limit.