price?
10 NXT
10 NTX for whole lot or 10 NXT per share?
IF pool generates 7 BTC per week, then each share mines 7*0.01*0.00001 = 0.0000007 BTC week. The full 32000 shares only mines 0.0224 BTC week. That's about 364 NXT per week or 364/3200 = 0.11275 NXT per share per week.
2 Month RIO seems reasonable for mining.
Price for RIO in 2 months would be approx. 10*0.11275 = 1.1275 NXT per share.
This ignores increases in difficulty and fluctuations in NXT price.
Clearly 10 NXT per asset and not 10 NTX for the entire operation!
You are assuming 100% of revenues are returned, but it turns out that 60% return is closer to optimal as the 40% reinvested in more hashrate will compound so that you end up with approx the same payback time, but instead of staying with the same hashrate, your hashrate has increased.
So, no promises on 2 to 3 month payback. One possibility is that after capital is fully paid back, we might go into a much lower payout for a bit to be able to get the next generation hardware. All of these decisions will be made to maximize the long term ROI and not to stick to any hardcoded payout levels.
Adaptability is key to success, especially when the landscape changes so fast.
James