Laying or spacers..

So after picking our spiderties at the Hilo shipping port warehouse we headed back to lay our 350 pieces of J rebar (#4 1/2 inch).. Our engineer suggested this would be best done after we poured the concrete while it was soft and then put it in. We thought it about, however since each bar is 2 feet long with a 5 inch bend at the bottom and only 8 inches would be under the concrete we weren't confident that this would stand still in the concrete without tilting over. Its very critical that we maintain a 6 inch clearance from the edge of the concrete pour/slab. Because 4 inches are for the footing and then the wall begins. Since we want the steel to be imbedded inside the wall at least an inch we set it back 6 inches. However we don't want to be too far in because it will interfere with our water stop product. We tried wiring in three places yesterday evening and even then it would wiggle and we couldn't keep it in place where we wanted. Anyway, we bought 35 pieces of 2x4 and cut them up into small pieces which were 24.4cm long to get the length we needed.