TechTool Pro 4 has a feature that does away with the need for a bootable CD called eDrive. The eDrive very neatly gets around problems that have plagued both Micromat and Alsoft trying to keep up with the rapid advance of OS X. When you install TTP 4 go to the Tools panel and click on eDrive. You can use this to non-destructively create, or later remove, an invisible, bootable partition on your hard drive using a stripped down copy of OS X copied from your own hard drive along with a copy of TTP 4. The eDrive takes 4 GB of your hard drive for the new partition - and no you cannot change the size, it is the minimum deemed necessary for proper operation and since it is a stripped down version of OS X other utilities may or may not be able to run in the eDrive environment.
You boot from the eDrive either from within TTP 4 or by holding down the option key when you boot. The eDrive is better than using a CD because many of the TTP routines work much better with access to virtual memory and you cannot use virtual memory when booted from a CD.
By-the-way, like the OS X install CDs, the TTP 4 bootable CD does not have a Finder and is limited strictly to running or installing TTP 4.