Contemplating the same thing. I’m going for the traditional waterwheel. The microhydros are usually lower power, and the higher rpm usually Pelton turbines, while being higher efficiency dynamically, suffer larger frictional losses both in the bearings and the turbine box. Pelton turbines are best with massive volume and velocity with large diameter turbines operating at low rpm. Usually this is not feasible in small scale power production. Waterwheels produce massive torque that can easily be converted to alternator relevant rpm using bicycle gearing, and as an added bonus, the ratio is easily adapted to the available torque. The waterwheel I’m building is undershot, and will be roughly 4 meters in diameter. I hope this helps!