It's an interesting idea, but it gets difficult to know what octane(and energy content) the fuel is when two are mixed in uncertain amounts. Methanol also requires a much larger injector than gas, so using the same one for both fuels would be compromise. Fortunately there is the option of staged injection. It would allow the existing fuel system and injectors to handle gasoline while a second set injected only methanol. The ECU would then be able to scale back the amount of gas injected based in a predictable manner.
Then again, there is the option of just running straight E85. The MS code allows for adding a flex fuel sensor too.