Agree this firm gives large buying power - but I never saw a salary (If its the firm mentioned earlier in the link) - they also don't necessarily like overnights. After all prop. firms make most of their money on churn.
As others have said, it doesn't seem like a great deal either way. However, to answer your question, it's a simple math problem: x = gross profits in cents per share 0.29x = 0.65 (x - 0.75) => x = 1.354 cents per share => If your system makes a profit of 1.354 cents per share, then both systems will give you the identical return (both will let you 'take home' 0.39 cents per share traded). => If your average profits are ABOVE 1.354 cents per share, then you will be better off with the 0.0075 commission 'deal'. => If your average profits are BELOW 1.354 cents per share, then you will be better off with zero commission 'deal'.