Ive noticed your calculation for 50 shares is wrong, it should be 14.8 BTC.
An 15% investment in growth per month seems low to me, as the difficulty is rising much faster. Could you provide an update of those numbers with current exchange rate and difficulty?
Also, a projection of 1) difficulty and return of Bitcoins and 2) more details on future competitiveness (others have advantages such as free electricity or power-efficient custom hardware) would be interesting. Perhaps upgrading to a location with lower electricity costs, more efficient hardware etc.
Thanks for doing this, Im definitely interested in investing in such a venture. My only real issue here is trust, as you arent very reputable on this forum yet.