I've seen concrete gangs using tubing suspended on tripod stools made from three L-shared rebars. The short leg of the L's (about 6") are welded together in a triangle making a tripod with a triangle hole in the top. A length of dywidag bar is dropped from the middle of the tripod with the end bent as a hook to carry a scaffold tube. Several are used to suspend the tube and make it level and the pour is levelled from this. When the pour is in pull out the stools and float the surface.
Peter - novice home machinist, modern motorcycle enthusiast.
Denford Viceroy 280 Synchro (11 x 24)
Herbert 0V adapted to R8 by 'Sir John'.