Any perticular reason the Dynaco preamp? Not what i would call a great pramp and the tube types are getting harder to find. If you have it already fine it will do but it will be the week link in your system.
As for tubes and where, preamp first and power amp second. Power tubes are much more expencive then preamp tubes and do not last nearly as long. I would always go a tube preamp and SS amp over a SS preamp and tube amp. If you have efficent speakers maybe a tube amp as well. I'm not a fan of big power tube amps they seem to lose something as they get more powerful.