Make mst, then you can install it silently with customization as you need. But this type of installation no need to modified msi. If you want to reduce size of installer, you can modify msi and make any customization as you need for the installer. I have made a switchless installer for acdsee8pro and the size is only 11mb. Original size is 24mb. I remove all plugins, just only main program available. If you like to share, i will upload it to you.