Honestly, renting Hash rate is not a solution, especially on this pool, since $30 times 30 days is 900 dollars. Approximately 17 days to get full share for shares provided to the pool at 7.8TH. It truly is a gamble since we may hit 20 blocks or 5 in those 30 days and subsequent Ramp Down within the Payout period for the Shares you provided. You would be much better off just buying a Used miner like a S7 or Avalon 741 if you can get one and mine consistently over time. That way, while there is variance in when the pool hits a block, once you have your 5 times difficulty into the pool at your Hash Rate, you are going to get the maximum possible payout per block. That is all I got for you. Good Luck. If you want to compute possible Return on Investment, go here. http://tradebtc.net/bitcalc.php  I can tell you already that it doesn't look good for 7.8 TH/s. You would need a lot of luck.