There are many diffrent spreader sprayer machines are out on the market now. Some go as fast as 8 mph but are your applications done properly and evenly, even the small areas on large lawns at that speed 8 mph, seems a bit too fast? I know changing the speed you need to change calibration, the hopper opening size, spray nozzles, pressure or amount of concentrate added to your spray solution. Too much variable speed can cost you a lot of money over time in wasted materials or not applying the right amount of products. The question is, what is the best speed you find being the most efficient speed, 3.5, 5, 6.5 or 8 mph to do applications??