Did the rebuild include a rebore? Only after a rebore should you use hard rings such as chrome or moly. If you did rebore, you need to make sure the machine shop cross hatched the cylinders after they bored them. If you used cast iron rings, then I agree that you just drive it and see if it gets better. Did you work the head too? It doesn't take much oil for blue smoke, and oil can get by worn valve guides.