1) What is the maximum RPM the WindTura 750 can operate at constant speed and the wattage produced at max speed? 2) What is the life expectancy of WindTura 750 when run constantly at maximum speed? 3) Do you sell Grid tie Inverter that is compatible with Windtura 750...if not what would you recommend (ie. Ginlong GCI 2K? 4) What is the difference between Ginlong GL-PMG 1000 and Windtura750 product?