I also got this to work in Mac OS 9.0.4 running SheepShaver 2.4 (20140201).
I downloaded the "GTQ Scripting Library 1.2.1" .hqx archive from
http://www.info-mac.org/viewtopic.php?f ... ng+Library and installed just the "Set Depth to" scripting addition in OS 9.0.4's "System Folder/Scripting Additions" folder, as per emendelson's suggestion.
I downloaded the AppleScript 1.4.3 (International Version) installer from
http://www.gla.ac.uk/~gwm1h/macos9/ because both 1.6 and 1.8.3 are too new for OS 9.0.4.
In case you are wondering, I didn't have Apple's Script Editor installed in my system, because I run a very lean 9.0.4 so that SheepShaver runs as quickly and as efficiently as possible.
Once AppleScript was installed, I just created a new script with just the lines . . .
set depth to 16
set depth to 32
. . . as the OP explained.
I saved it as a "classic applet" and placed it in my main "AppleScript" folder -- normally found in the "Apple Extras" folder -- and then put an alias of it on my SheepShaver desktop.
Whenever my screen turns blue, I just double-click the desktop alias. I find that it is a lot quicker and easier than having to do the following:
1. Select "Control Panels" under the Apple menu.
2. Select the "Monitors" control panel.
3. Switch the color depth to "Thousands".
4. Switch the color depth back to "Millions".
5. Close the "Monitors" control panel.
You could just downgrade to "SheepShaver_10-25-2009_UB.zip" as Ronald P. Regensburg suggests in other posts, in order to get rid of the blue screen problem. However, by doing so, you will lose some of the functionality that was added in SheepShaver 2.4 (20140201). You may possibly also mess up other parts of your SheepShaver installation, by accident. That made me a bit nervous, so I went the script route instead.
It's your choice. I personally just prefer to click my desktop script alias.