I don’t know if this is officially supported, but I found a way to do this by editing a text file in the installer. It’s a good idea to create a backup copy of the installer, as we’ll be messing with it.
Assuming you have the installer displayed, right-click it and choose Show Package Contents. (The installer package is in fact a folder.)
You should see a Contents folder. Within that, a file called distribution.dist. Open it with a text editor such as Sublime Text.
Scroll down until you see a markup element called <choices-outline>. Within that there are sub-elements such as <line choice=“word”/>.
Each of those represents one of the checkboxes that is displayed on the Customize screen of the installer. Remove the ones you don’t think are necessary. For me, I removed all of the Proofing Tools except my native language. I also removed Outlook. I left the appsupport and fonts alone, I figured they are good things. I got rid of VB.
Save the file and re-launch the installer. You should notice that the install size is now smaller, and if you choose to Customize the install, there are many fewer options.
You can repeat as necessary – remove elements, re-launch the install, see the difference.
Hope this helps! Be careful. Make a backup!