Good luck finding 200 proof. Even that will pull moisture if your not careful or you leave it in your tank for a long while. You need to add 1-2% propylene oxide if you want them to be kept in solution for a long time.
im just shooting darts here, but does'nt using a higher octane (more that 87)for the 800 affect it's engine in anyway keeping in mind it has a very low compression ratio in comparision to other cars?