As far as the shock orings go, get yourself some of the Kyosho X type orings. They are a perfect fit and due to the x seal design there is more suface contact on the shaft which makes the shocks heaps smoother and they dont leak like the Tamiya ones do. I did it with mine along with the rod and guide kit option and it was the best thing I ever did to the shocks.
Also try and build the shocks in the same manner as you would an associated shock and not use the bleed screws, much better for setting rebound right.