Single MSI to install correct 32 or 64 bit c# application

Question

I have a C# application which is built for both x86 (32 bit) and x64 (64 bit) platforms. My build system currently outputs two MSI installers, one for each platform. In case

Answer 1

No, this is not possible. See Heath Stewart's Different Packages are Required for Different Processor Architectures post. The only way to handle this with MSI is with a bootstrap along the lines of what you describe. If you just needed to put a file or key or two in a 64-bit location, it's possible (but not recommended) to do that in a custom action, but changing the target installation location and using built-in MSI file support won't work.