Windows 16-bit and 32-bit Setup
install-us FAQ

"Can I distribute one set of installation files for all the different versions of Windows, such as Win95 and Win 3.1?" In other words, will setup.exe automatically determine whether it has to run the 16-bit or the 32-bit installation?"

Answer: Yes. Go to section "1 - General Settings" and click on "Windows..." Choose "automatic detection" in the dialog box. Please note that the installation will become larger and need more disk space.