We currently have a 4kw Solar Edge system installed on our house roof in sunny south east Kent, which was installed in 2015, so earn reasonable FITS from it. We have a detached double garage with flat roof, which is 5.7  x 5.93 meters south westerly facing, dependant on spacing of the panels we could fit at most 12 panels on it. There are two tree's that would cause early morning and late afternoon shading, which is obviously worse in the winter, but for the main part of the day it is unshaded a