I used over the counter L brackets. Just about any metal attachment configuration would work, I would use your big foot brackets. We like the jacks, get a lot of looks at campgrounds. We ordered our coach and picked them as an option..
Used the coffee can for the radius. They stay in place by themselves as there is a slight channel on the inside of the window. Have not moved in over 8000 miles. The board is from Walmart for under 2 bucks. I think 1/4 thick.