The Gutter is installed on the fascia with the non-downspout end high and the downspout end low. According to manufacturer specifications the gutter should drop 1 inch every 16 linear feet. Also, the gutter should be approximately ¼ inch to ¾ inch lower than the extended roof line. See Berger Product catalog for details.
The length of time to complete your job varies based on multiple factors. Below is a list of basic ranges to give you a idea of what to expect. Cleaning between 1-3 hours New install between 2-6 hours Removal and Installation between 4-6 hours Retrofit leaf covers between 2-3 Hours
Yes. Most debris will blow off covers in a normal breeze. Wet debris may need a wind in the range of 20-25mph. PlyGem, the manufacturer of the Leaf Relief product, states that gutters should be cleaned at least once a year.