Funny thing I have recalled just now - about somebody's suggestion to not drive the screws into plywood alone.
When I removed TV antenna that was getting in the way of the front solar panel, I found that it was attached with two #10 screws into 3/8" OSB. Pretty big and heavy "mushroom" antenna, feels like 7 or 8 lbs, about 1ft tall and 1ft diameter at the top. The screws were not stainless, and were not even wood screws - they were in fact sheet metal M4.5 metric screws. This size is close to #10 but the thread is for a sheet metal, not as good grip in plywood as deck screws. Those m.orons were simply using whatever fasteners they had, no matter whether in metal or wood. Being an automotive-ish industry, they had metric screws. Thor Industries, reputable old company.