JOH
You had another post today under Research and Development related to this project you are working on. IMHO you might find a more complete solution if you used the same thread to work toward completion. In Post #8 of the R&D thread there is a reference to clamps I bought several months ago for this purpose. The roof only weighs 49 kg. Gutter mount brackets are no longer easy to find but will do the job. I do reccomend some sort of back up with these.
