Sodium hydroxide melts at a much lower temperature than NaCl, and can be used to make Na. I have done it small scale a few times.
Using NaCl, even if you can achieve the 800C, if you do not have fine temperature control, the Na will actually dissolve in the molten NaCl. I tried this a few times without luck, while with molten NaOH I was able to isolate a few cubic centimeters at a time.
Also, NaCl at 800C has a noticeable vapour pressure, and it creates a metallic taste in your mouth from inhaling the vapour. Not fun. Just use NaOH.
Mandatory safety warning: molten NaOH is damn corrosive. Be careful.