Paying for real-time market data

At Interactive Brokers, I got to pay USD 10 per month for real-time market data (US Securities & Commodities Non-Professional Bundle). Therefore, I must make full use of the money I'm paying for.

I decided to build my own historical database using IB's feeds. According to here http://www.interactivebrokers.com/en/p.php?f=marketData

All customers initially receive 100 concurrent lines of real-time market data (which can be displayed in TWS or via the API) and always have a minimum of 100 lines of data.

I think I can make use of at least 80 concurrent lines of real-time market data to build my historical database via the API. Whereas I can leave the remaining 20 concurrent lines of real-time market data for TWS.