I will add 2 x 4" between the old walnut stringers. That way there will be a support every 24". I will test it out and let you know how it works.
I love your innovative ideas and kind help. I have an old building in Kansas that the termites got to the floor. There is a partial basement so all that is left are 14" x 4" solid walnut stringers about 4' apart. I was wondering if I could use the little dragon system and build 3" x 4' x 8' slabs and then attach them to the old walnut stringers. Do you think there would be enough strength doing this? I felt that by adding one or two supporting 2 x 6 it should handle anything.... your thoughts? I am building a distillery there. Quit the oilfield and want something more fun.