Hi Bob,
Cool ideas! I have some additional information that might prove helpful when using this approach.
In both cases (overclocking or underclocking), a good way to change the frequency-dependent parameters (filters, timers, and so forth) in you project is to follow this guide: FAQ: How do I change the samplerate of my SigmaStudio system?
By following the instructions in the section labeled Setting "Non-Standard" Software Sample Rates, you can very easily change the sample rate of your system to any arbitrary frequency, without having to go in and manually change any of the filter settings in the project.