That branch looks like you're on the right track. The build scripts in 
Tools/msi should Just Work, so I'd be interested to see the error you get.

You can also submit it as a PR and the MSI will be built automatically.

One thing I noticed is updating the name of the "Add Python to PATH" 
option, which I'd rather keep as "Add" since we won't have both options 
in the UI. The word "Prepend" is quite obscure jargon, and for the range 
of users we have it isn't fair to expect them to know it (or to break 
all of the guidance out there explaining that checkbox already).