I sure would like to see someone do some math on this.
IMHO there are two many unknown variables to get any meaningful recommandation based on any math. Mainly unpredictable difficulty and because we don't see volume pricing Lab_Rat is getting. However my gut feeling and common sense is telling me we should be in the try-to-keep-up-with-difficulty mode whatever it costs (in other words 100% reinvestment).
The more I think about it, the more I would love to have different contract with Lab_Rat, which would be e.g. like this: For the funds you got during the first round of funding, you must control at least 1% of total bitcoin network hashrate and pay all excesive profit to bondholders.
This would untie Lab_Rat his hands and would LOOK riskier to bond holders, but it actually isn't. The reason is Lab_Rat would have more resources to fight diffuculty, which means more stable dividends in the LONG TERM. And even if he doesn't manage to keep up with difficulty and bond holders would not see any profit, then what does it matter because even in current contract we would not see any significant ROI. So I'm very glad LR has at least those 14 days mining towards direct reinvestment in the contract.
I think you should ONLY do things based on recommendations backed by reasonable math. Why would making reinvestment 100% improve the value of the offering, just because it feels good?
The math isn't that hard, and there are just two variables (time to delivery and difficulty rate)
HR=device hashrate you want to buy
NET=network hashrate at time you start hashing (need to estimate)
tau=1/e lifetime of your device (mining half life of the device), in days which also is the exponential difficulty growth rate
CURRENT=current network hashrate
T=time, in days, until delivery
If you guess what the network rate will be when it arrives and have an estimate of difficulty growth rate
HR/NET*3600*tau < the cost (in BTC) of the device you want to buy, DO NOT BUY IT
or if you have an idea of when it will arrive and an estimate of difficulty growth rate:
HR/CURRENT*e^{-T/tau}*3600*tau < the cost (in BTC) of the device you want to buy, DO NOT BUY IT
The approximation is that growth will increase exponentially over the time frame of usable mining. Don't say "it can't sustain this forever" because over the next year it should fit somewhat of an exponential as gen2 devices come out, and it's just a model - use a bigger tau in that case... These are models, you need to figure out what your tau and T's are, and back them up and justify it. Use this for security valuation, hedge against difficulty and price variance risk with futures. Pick a reasonable high, low, medium for those 2 variables, make a 3x3 chart and figure out what you'd need to break even. Invest based primarily on that.
this doesn't take into account electricity, rent - you need to figure that in too.
background:
I value a device at
\int_0^\infty HR/NET*25*144*e^{-t/\tau} dt
and say that NET can be CURRENT*e^{-t/\tau}
EXAMPLE:
Monarchs, CURRENT = 5000 TH/s, HR=600GH/s, cost ~6.5
BTCvaluation is profitable if they deliver in 2 months and difficulty tau is 50 days (82% per month)
